diff --git a/RedPandaIDE/compiler/projectcompiler.cpp b/RedPandaIDE/compiler/projectcompiler.cpp
index 0bc52934..42384314 100644
--- a/RedPandaIDE/compiler/projectcompiler.cpp
+++ b/RedPandaIDE/compiler/projectcompiler.cpp
@@ -141,8 +141,7 @@ void ProjectCompiler::writeMakeDefines(QFile &file)
     QString cleanObjects;
 
     // Create a list of object files
-    for (int i=0;i<mProject->units().count();i++) {
-        PProjectUnit unit = mProject->units()[i];
+    foreach(const PProjectUnit &unit, mProject->unitList()) {
         if (!unit->compile() && !unit->link())
             continue;
 
@@ -324,8 +323,8 @@ void ProjectCompiler::writeMakeObjFilesRules(QFile &file)
     if (mProject->options().usePrecompiledHeader)
         precompileStr = " $(PCH) ";
 
-    for (int i = 0;i<mProject->units().count();i++) {
-        PProjectUnit unit = mProject->units()[i];
+    QList<PProjectUnit> projectUnits;
+    foreach(const PProjectUnit &unit, projectUnits) {
         FileType fileType = getFileType(unit->fileName());
         // Only process source files
         if (fileType!=FileType::CSource && fileType!=FileType::CppSource)
@@ -343,8 +342,7 @@ void ProjectCompiler::writeMakeObjFilesRules(QFile &file)
                     continue;
                 if (!parser->isSystemHeaderFile(headerName)
                         && ! parser->isProjectHeaderFile(headerName)) {
-                    for (int j = 0;j<mProject->units().count();j++) {
-                        PProjectUnit unit2 = mProject->units()[j];
+                    foreach(const PProjectUnit &unit2, projectUnits) {
                         if (unit2->fileName()==headerName) {
                             objStr = objStr + ' ' + genMakePath2(extractRelativePath(mProject->makeFileName(),headerName));
                             break;
@@ -353,10 +351,10 @@ void ProjectCompiler::writeMakeObjFilesRules(QFile &file)
                 }
             }
         } else {
-            foreach (const PProjectUnit& u, mProject->units()) {
-                FileType fileType = getFileType(u->fileName());
+            foreach(const PProjectUnit &unit2, projectUnits) {
+                FileType fileType = getFileType(unit2->fileName());
                 if (fileType == FileType::CHeader || fileType==FileType::CppHeader)
-                    objStr = objStr + ' ' + genMakePath2(extractRelativePath(mProject->makeFileName(),u->fileName()));
+                    objStr = objStr + ' ' + genMakePath2(extractRelativePath(mProject->makeFileName(),unit2->fileName()));
             }
         }
         QString ObjFileName;
@@ -449,7 +447,7 @@ void ProjectCompiler::writeMakeObjFilesRules(QFile &file)
         QString ResFiles;
         // Concatenate all resource filenames (not created when syntax checking)
         if (!mOnlyCheckSyntax) {
-            foreach(const PProjectUnit& unit, mProject->units()) {
+            foreach(const PProjectUnit& unit, mProject->unitList()) {
                 if (getFileType(unit->fileName())!=FileType::WindowsResourceSource)
                     continue;
                 if (fileExists(unit->fileName())) {
diff --git a/RedPandaIDE/cpprefacter.cpp b/RedPandaIDE/cpprefacter.cpp
index 281ba875..7d9330fd 100644
--- a/RedPandaIDE/cpprefacter.cpp
+++ b/RedPandaIDE/cpprefacter.cpp
@@ -177,7 +177,7 @@ void CppRefacter::doFindOccurenceInProject(PStatement statement, std::shared_ptr
                 statement->fullName,
                 SearchFileScope::wholeProject
                 );
-    foreach (const PProjectUnit& unit, project->units()) {
+    foreach (const PProjectUnit& unit, project->unitList()) {
         if (isCFile(unit->fileName()) || isHFile(unit->fileName())) {
             PSearchResultTreeItem item = findOccurenceInFile(
                         unit->fileName(),
diff --git a/RedPandaIDE/editor.cpp b/RedPandaIDE/editor.cpp
index 0375bb3e..151891a2 100644
--- a/RedPandaIDE/editor.cpp
+++ b/RedPandaIDE/editor.cpp
@@ -336,8 +336,8 @@ bool Editor::saveAs(const QString &name, bool fromProject){
     }
     // Update project information
     if (mInProject && pMainWindow->project() && !fromProject) {
-        int unitIndex = pMainWindow->project()->indexInUnits(newName);
-        if (unitIndex<0) {
+        int unitId = pMainWindow->project()->findUnitId(newName);
+        if (unitId<0) {
             mInProject = false;
         }
     }
@@ -423,9 +423,8 @@ void Editor::setEncodingOption(const QByteArray& encoding) noexcept{
     if (mInProject) {
         std::shared_ptr<Project> project = pMainWindow->project();
         if (project) {
-            int index = project->indexInUnits(this);
-            if (index>=0) {
-                PProjectUnit unit = project->units()[index];
+            PProjectUnit unit = project->findUnit(this);
+            if (unit) {
                 unit->setEncoding(mEncodingOption);
             }
         }
@@ -1740,7 +1739,7 @@ bool Editor::isBraceChar(QChar ch)
 
 bool Editor::shouldOpenInReadonly()
 {
-    if (pMainWindow->project() && pMainWindow->project()->findUnitByFilename(mFilename))
+    if (pMainWindow->project() && pMainWindow->project()->findUnit(mFilename))
         return false;
     return pSettings->editor().readOnlySytemHeader()
                 && mParser && (mParser->isSystemHeaderFile(mFilename) || mParser->isProjectHeaderFile(mFilename));
diff --git a/RedPandaIDE/editorlist.cpp b/RedPandaIDE/editorlist.cpp
index a626b4e7..1d7c789e 100644
--- a/RedPandaIDE/editorlist.cpp
+++ b/RedPandaIDE/editorlist.cpp
@@ -56,7 +56,7 @@ Editor* EditorList::newEditor(const QString& filename, const QByteArray& encodin
     connect(e, &Editor::renamed, this, &EditorList::onEditorRenamed);
     updateLayout();
     if (pMainWindow->project()){
-        PProjectUnit unit = pMainWindow->project()->findUnitByFilename(filename);
+        PProjectUnit unit = pMainWindow->project()->findUnit(filename);
         if (unit) {
             pMainWindow->project()->associateEditorToUnit(e,unit);
             e->setInProject(true);
@@ -169,9 +169,9 @@ bool EditorList::closeEditor(Editor* editor, bool transferFocus, bool force) {
 //    }
 
     if (editor->inProject() && pMainWindow->project()) {
-        int projIndex = pMainWindow->project()->indexInUnits(editor);
-        if (projIndex>=0) {
-            pMainWindow->project()->closeUnit(projIndex);
+        int unitId = pMainWindow->project()->findUnitId(editor);
+        if (unitId>=0) {
+            pMainWindow->project()->closeUnit(unitId);
         }
     } else {
         if (pSettings->history().addToOpenedFiles(editor->filename())) {
diff --git a/RedPandaIDE/mainwindow.cpp b/RedPandaIDE/mainwindow.cpp
index fd7aa524..45ebb9e9 100644
--- a/RedPandaIDE/mainwindow.cpp
+++ b/RedPandaIDE/mainwindow.cpp
@@ -1186,7 +1186,7 @@ void MainWindow::openFile(const QString &filename, bool activate, QTabWidget* pa
         pSettings->history().removeFile(filename);
         PProjectUnit unit;
         if (mProject) {
-            unit = mProject->findUnitByFilename(filename);
+            unit = mProject->findUnit(filename);
         }
         bool inProject = (mProject && unit);
         QByteArray encoding = unit ? unit->encoding() :
@@ -1260,8 +1260,7 @@ void MainWindow::openProject(const QString &filename, bool openFiles)
             mProject->doAutoOpen();
 
         //update editor's inproject flag
-        for (int i=0;i<mProject->units().count();i++) {
-            PProjectUnit unit = mProject->units()[i];
+        foreach (PProjectUnit unit, mProject->unitList()) {
             Editor* e = mEditorList->getOpenedEditorByFilename(unit->fileName());
             mProject->associateEditorToUnit(e,unit);
         }
@@ -2214,7 +2213,7 @@ void MainWindow::loadLastOpens()
             page = mEditorList->rightPageWidget();
         PProjectUnit unit;
         if (mProject) {
-            unit = mProject->findUnitByFilename(editorFilename);
+            unit = mProject->findUnit(editorFilename);
         }
         bool inProject = (mProject && unit);
         QByteArray encoding = unit ? unit->encoding() :
@@ -3022,7 +3021,7 @@ void MainWindow::onProjectViewContextMenu(const QPoint &pos)
                     shouldAdd=false;
                     break;
                 }
-                PProjectUnit pUnit=mProject->units()[node->unitIndex];
+                PProjectUnit pUnit=mProject->findUnitById(node->unitIndex);
                 if (mProject->model()->iconProvider()->VCSRepository()->isFileInRepository(
                             pUnit->fileName()
                             )
@@ -3919,7 +3918,7 @@ void MainWindow::onProjectAddFolder()
                           QLineEdit::Normal, s,
                           &ok).trimmed();
     if (ok && !s.isEmpty()) {
-        QString path = mProject->getFolderPath(folderNode);
+        QString path = mProject->getNodePath(folderNode);
         if (path.isEmpty()) {
             mProject->addFolder(s);
         } else {
@@ -5915,10 +5914,9 @@ void MainWindow::on_actionAdd_to_project_triggered()
                             );
             }
         }
-        mProject->rebuildNodes();
         mProject->saveUnits();
+        updateProjectActions();
         parseFileList(mProject->cppParser());
-        updateProjectView();
     }
 }
 
@@ -5929,8 +5927,11 @@ void MainWindow::on_actionRemove_from_project_triggered()
         return;
     if (!ui->projectView->selectionModel()->hasSelection())
         return;
-    mProject->model()->beginUpdate();
-    QSet<int> selected;
+
+    bool removeFile = (QMessageBox::question(this,tr("Remove file"),
+                              tr("Remove the file from disk?"),
+                              QMessageBox::Yes | QMessageBox::No) == QMessageBox::Yes);
+
     foreach (const QModelIndex& index, ui->projectView->selectionModel()->selectedIndexes()){
         if (!index.isValid())
             continue;
@@ -5939,22 +5940,10 @@ void MainWindow::on_actionRemove_from_project_triggered()
         PProjectModelNode folderNode =  mProject->pointerToNode(node);
         if (!folderNode)
             continue;
-        selected.insert(folderNode->unitIndex);
+        mProject->removeUnit(folderNode->unitIndex, true, removeFile);
     };
-
-    bool removeFile = (QMessageBox::question(this,tr("Remove file"),
-                              tr("Remove the file from disk?"),
-                              QMessageBox::Yes | QMessageBox::No) == QMessageBox::Yes);
-
-    for (int i=mProject->units().count()-1;i>=0;i--) {
-        if (selected.contains(i)) {
-            mProject->removeUnit(i,true,removeFile);
-        }
-    }
-
     mProject->saveUnits();
-    mProject->model()->endUpdate();
-    updateProjectView();
+    updateProjectActions();
 }
 
 
@@ -6135,7 +6124,6 @@ void MainWindow::newProjectUnitFile()
 {
     if (!mProject)
         return;
-    int idx = -1;
     QModelIndex current = mProjectProxyModel->mapToSource(ui->projectView->currentIndex());
     ProjectModelNode * node = nullptr;
     if (current.isValid()) {
@@ -6217,11 +6205,11 @@ void MainWindow::newProjectUnitFile()
     newUnit = mProject->newUnit(
                     pNode,newFileName);
 
-    mProject->rebuildNodes();
+//    mProject->rebuildNodes();
     mProject->saveAll();
-        updateProjectView();
-    idx = mProject->units().count()-1;
-    Editor * editor = mProject->openUnit(idx, false);
+//        updateProjectView();
+//    idx = newUnit->id;
+    Editor * editor = mProject->openUnit(newUnit->id(), false);
     //editor->setUseCppSyntax(mProject->options().useGPP);
     //editor->setModified(true);
     if (editor)
@@ -6233,7 +6221,7 @@ void MainWindow::newProjectUnitFile()
         mProject->model()->beginUpdate();
         mProject->model()->endUpdate();
     }
-    updateProjectView();
+    updateProjectActions();
 }
 
 void MainWindow::fillProblemCaseInputAndExpected(const POJProblemCase &problemCase)
@@ -7484,7 +7472,7 @@ void MainWindow::on_actionGit_Create_Repository_triggered()
         QString output;
         vcsManager.add(mProject->folder(), extractFileName(mProject->filename()), output);
         vcsManager.add(mProject->folder(), extractFileName(mProject->options().icon), output);
-        foreach (PProjectUnit pUnit, mProject->units()) {
+        foreach (PProjectUnit pUnit, mProject->unitList()) {
             vcsManager.add(mProject->folder(),extractRelativePath(mProject->folder(),pUnit->fileName()),output);
         }
         //update project view
@@ -7528,7 +7516,7 @@ void MainWindow::on_actionGit_Add_Files_triggered()
             if (!folderNode)
                 continue;
             if (folderNode->unitIndex>=0) {
-                PProjectUnit unit = mProject->units()[folderNode->unitIndex];
+                PProjectUnit unit = mProject->findUnitById(folderNode->unitIndex);
                 QFileInfo info(unit->fileName());
                 QString output;
                 vcsManager.add(info.absolutePath(),info.fileName(),output);
diff --git a/RedPandaIDE/mainwindow.ui b/RedPandaIDE/mainwindow.ui
index b1a08985..301dca55 100644
--- a/RedPandaIDE/mainwindow.ui
+++ b/RedPandaIDE/mainwindow.ui
@@ -473,7 +473,7 @@
      <enum>QTabWidget::West</enum>
     </property>
     <property name="currentIndex">
-     <number>4</number>
+     <number>1</number>
     </property>
     <property name="usesScrollButtons">
      <bool>true</bool>
diff --git a/RedPandaIDE/project.cpp b/RedPandaIDE/project.cpp
index f91aab0b..06be81cd 100644
--- a/RedPandaIDE/project.cpp
+++ b/RedPandaIDE/project.cpp
@@ -190,9 +190,12 @@ void Project::open()
         }
         newUnit->setNew(false);
         newUnit->setParent(this);
-        newUnit->setNode(makeNewFileNode(extractFileName(newUnit->fileName()), false, folderNodeFromName(newUnit->folder())));
-        newUnit->node()->unitIndex = mUnits.count();
-        mUnits.append(newUnit);
+        PProjectModelNode node = makeNewFileNode(extractFileName(newUnit->fileName()),
+                                                 newUnit->id(),
+                                                 newUnit->priority(),
+                                                 folderNodeFromName(newUnit->folder()));
+        newUnit->setNode(node);
+        mUnits.insert(newUnit->id(),newUnit);
     }
     rebuildNodes();
 }
@@ -215,7 +218,9 @@ void Project::setModified(bool value)
     }
 }
 
-PProjectModelNode Project::makeNewFileNode(const QString &s, bool isFolder, PProjectModelNode newParent)
+PProjectModelNode Project::makeNewFolderNode(
+        const QString &folderName, PProjectModelNode newParent,
+        ProjectModelNodeType nodeType,int priority)
 {
     PProjectModelNode node = std::make_shared<ProjectModelNode>();
     if (!newParent) {
@@ -223,17 +228,35 @@ PProjectModelNode Project::makeNewFileNode(const QString &s, bool isFolder, PPro
     }
     newParent->children.append(node);
     node->parent = newParent;
-    node->text = s;
+    node->text = folderName;
     if (newParent) {
         node->level = newParent->level+1;
     }
-    if (isFolder) {
-        node->unitIndex = -1;
-        node->priority = 0;
-        node->folderNodeType = ProjectModelNodeType::Folder;
-    } else {
-        node->folderNodeType = ProjectModelNodeType::File;
+    node->unitIndex = -1;
+    node->priority = priority;
+    node->folderNodeType = nodeType;
+    QModelIndex parentIndex=mModel.getNodeIndex(newParent.get());
+    mModel.insertRow(newParent->children.count(),parentIndex);
+    return node;
+}
+
+PProjectModelNode Project::makeNewFileNode(const QString &fileName, int unitId,int priority, PProjectModelNode newParent)
+{
+    PProjectModelNode node = std::make_shared<ProjectModelNode>();
+    if (!newParent) {
+        newParent = mRootNode;
     }
+    newParent->children.append(node);
+    node->parent = newParent;
+    node->text = fileName;
+    if (newParent) {
+        node->level = newParent->level+1;
+    }
+    node->unitIndex = unitId;
+    node->priority = priority;
+    node->folderNodeType = ProjectModelNodeType::File;
+    QModelIndex parentIndex=mModel.getNodeIndex(newParent.get());
+    mModel.insertRow(newParent->children.count(),parentIndex);
     return node;
 }
 
@@ -269,16 +292,17 @@ PProjectUnit Project::newUnit(PProjectModelNode parentNode, const QString& custo
         s = dir.absoluteFilePath(customFileName);
     }
     // Add
-    int count = mUnits.count();
-    mUnits.append(newUnit);
 
     // Set all properties
     newUnit->setFileName(s);
     newUnit->setNew(true);
-    newUnit->setFolder(getFolderPath(parentNode));
-    newUnit->setNode(makeNewFileNode(extractFileName(newUnit->fileName()),
-                                     false, parentNode));
-    newUnit->node()->unitIndex = count;
+    newUnit->setFolder(getNodePath(parentNode));
+    PProjectModelNode node = makeNewFileNode(extractFileName(newUnit->fileName()),
+                                             newUnit->id(),newUnit->priority(),parentNode);
+    node->unitIndex = newUnit->id();
+    newUnit->setNode(node);
+    mUnits.insert(newUnit->id(), newUnit);
+
     //parentNode.Expand(True);
     switch(getFileType(customFileName)) {
     case FileType::CSource:
@@ -311,10 +335,10 @@ PProjectUnit Project::newUnit(PProjectModelNode parentNode, const QString& custo
 
 Editor *Project::openUnit(int index, bool forceOpen)
 {
-    if ((index < 0) || (index >= mUnits.count()))
-        return nullptr;
 
-    PProjectUnit unit = mUnits[index];
+    PProjectUnit unit = mUnits.value(index,PProjectUnit());
+    if (!unit)
+        return nullptr;
 
     if (!unit->fileName().isEmpty() && fileExists(unit->fileName())) {
         if (getFileType(unit->fileName())==FileType::Other) {
@@ -353,6 +377,15 @@ Editor *Project::unitEditor(const ProjectUnit *unit) const
     return mEditorList->getOpenedEditorByFilename(unit->fileName());
 }
 
+QList<PProjectUnit> Project::unitList()
+{
+    QList<PProjectUnit> units;
+    foreach(PProjectUnit unit, mUnits) {
+        units.append(unit);
+    }
+    return units;
+}
+
 void Project::rebuildNodes()
 {
     mModel.beginUpdate();
@@ -366,35 +399,34 @@ void Project::rebuildNodes()
     switch(mOptions.modelType) {
     case ProjectModelType::Custom:
         createFolderNodes();
-
-        for (int idx=0;idx<mUnits.count();idx++) {
-            QFileInfo fileInfo(mUnits[idx]->fileName());
-            mUnits[idx]->setNode(
+        foreach (PProjectUnit pUnit, mUnits) {
+            QFileInfo fileInfo(pUnit->fileName());
+            pUnit->setNode(
                         makeNewFileNode(
                             fileInfo.fileName(),
-                            false,
-                            folderNodeFromName(mUnits[idx]->folder())
+                            pUnit->id(),
+                            pUnit->priority(),
+                            folderNodeFromName(pUnit->folder())
                             )
                         );
-            mUnits[idx]->node()->unitIndex = idx;
-            mUnits[idx]->node()->priority = mUnits[idx]->priority();
+            pUnit->node()->priority = pUnit->priority();
         }
         break;
     case ProjectModelType::FileSystem:
         createFileSystemFolderNodes();
 
-        for (int idx=0;idx<mUnits.count();idx++) {
-            QFileInfo fileInfo(mUnits[idx]->fileName());
-            mUnits[idx]->setNode(
+        foreach (PProjectUnit pUnit, mUnits) {
+            QFileInfo fileInfo(pUnit->fileName());
+            pUnit->setNode(
                         makeNewFileNode(
                             fileInfo.fileName(),
-                            false,
+                            pUnit->id(),
+                            pUnit->priority(),
                             getParentFolderNode(
-                                mUnits[idx]->fileName())
+                                pUnit->fileName())
                             )
                         );
-            mUnits[idx]->node()->unitIndex = idx;
-            mUnits[idx]->node()->priority = mUnits[idx]->priority();
+            pUnit->node()->priority = pUnit->priority();
         }
 
         break;
@@ -404,17 +436,12 @@ void Project::rebuildNodes()
     emit nodesChanged();
 }
 
-bool Project::removeUnit(int index, bool doClose , bool removeFile)
+bool Project::removeUnit(int id, bool doClose , bool removeFile)
 {
-    mModel.beginUpdate();
-    auto action = finally([this]{
-        mModel.endUpdate();
-    });
-    if (index<0 || index>=mUnits.count())
+    PProjectUnit unit = findUnitById(id);
+    if (!unit)
         return false;
 
-    PProjectUnit unit = mUnits[index];
-
 //    qDebug()<<unit->fileName();
 //    qDebug()<<(qint64)unit->editor();
     // Attempt to close it
@@ -432,12 +459,20 @@ bool Project::removeUnit(int index, bool doClose , bool removeFile)
 
 //if not fUnits.GetItem(index).fNew then
     PProjectModelNode node = unit->node();
-    PProjectModelNode parent = node->parent.lock();
-    if (parent) {
-        parent->children.removeAll(node);
-    }
-    mUnits.removeAt(index);
-    updateNodeIndexes();
+    PProjectModelNode parentNode = node->parent.lock();
+    if (!parentNode)
+        return true;
+    QModelIndex parentIndex = mModel.getParentIndex(unit->node().get());
+
+    int row = parentNode->children.indexOf(unit->node());
+    if (row<0)
+        return true;
+    parentNode->children.removeAt(row);
+
+    mUnits.remove(unit->id());
+
+    mModel.removeRow(row,parentIndex);
+
     setModified(true);
     return true;
 }
@@ -495,7 +530,7 @@ void Project::saveLayout()
     for (int i=0;i<mEditorList->pageCount();i++) {
         Editor* e= (*mEditorList)[i];
         if (e && e->inProject())
-            sl.append(QString("%1").arg(indexInUnits(e)));
+            sl.append(QString("%1").arg(findUnitId(e)));
     }
     layIni.SetValue("Editors","Order",sl.join(",").toUtf8());
 
@@ -503,11 +538,10 @@ void Project::saveLayout()
     // Remember what files were visible
     mEditorList->getVisibleEditors(e, e2);
     if (e)
-        layIni.SetLongValue("Editors","Focused", indexInUnits(e));
+        layIni.SetLongValue("Editors","Focused", findUnitId(e));
     // save editor info
-    for (int i=0;i<mUnits.count();i++) {
-        QByteArray groupName = QString("Editor_%1").arg(i).toUtf8();
-        PProjectUnit unit = mUnits[i];
+    foreach (const PProjectUnit& unit,mUnits) {
+        QByteArray groupName = QString("Editor_%1").arg(unit->id()).toUtf8();
         Editor* editor = unitEditor(unit);
         if (editor) {
             layIni.SetLongValue(groupName,"CursorCol", editor->caretX());
@@ -530,51 +564,22 @@ void Project::saveLayout()
     layIni.SaveFile(changeFileExt(filename(), "layout").toLocal8Bit());
 }
 
-void Project::saveUnitAs(int i, const QString &sFileName, bool syncEditor)
+void Project::renameUnit(int idx, const QString &sFileName)
 {
-    if ((i < 0) || (i >= mUnits.count()))
+    PProjectUnit unit = findUnitById(idx);
+    if (!unit)
         return;
-    PProjectUnit unit = mUnits[i];
     if (fileExists(unit->fileName())) {
         unit->setNew(false);
     }
     Editor * editor=unitEditor(unit);
-    if (editor && syncEditor) {
+    if (editor) {
         //prevent recurse
         editor->saveAs(sFileName,true);
     }
     unit->setNew(false);
     unit->setFileName(sFileName);
-    SimpleIni ini;
-    ini.LoadFile(mFilename.toLocal8Bit());
-    QByteArray groupName = toByteArray(QString("Unit%1").arg(i+1));
-    ini.SetValue(
-                groupName,
-                "FileName",
-                toByteArray(
-                    extractRelativePath(
-                        directory(),
-                        sFileName)));
-    ini.SaveFile(mFilename.toLocal8Bit());
     setModified(true);
-    if (!syncEditor) {
-        //the call it's from editor, we need to update model
-        mModel.beginUpdate();
-        mModel.endUpdate();
-    }
-}
-
-void Project::saveUnitLayout(Editor *e, int index)
-{
-    if (!e)
-        return;
-    SimpleIni layIni;
-    QByteArray groupName = (QString("Editor_%1").arg(index)).toUtf8();
-    layIni.SetLongValue(groupName,"CursorCol", e->caretX());
-    layIni.SetLongValue(groupName,"CursorRow", e->caretY());
-    layIni.SetLongValue(groupName,"TopLine", e->topLine());
-    layIni.SetLongValue(groupName,"LeftChar", e->leftChar());
-    layIni.SaveFile((changeFileExt(filename(), "layout")).toLocal8Bit());
 }
 
 bool Project::saveUnits()
@@ -584,9 +589,10 @@ bool Project::saveUnits()
     SI_Error error = ini.LoadFile(mFilename.toLocal8Bit());
     if (error != SI_Error::SI_OK)
         return false;
-    for (int idx = 0; idx < mUnits.count(); idx++) {
-        PProjectUnit unit = mUnits[idx];
-        QByteArray groupName = toByteArray(QString("Unit%1").arg(count+1));
+    int i=0;
+    foreach (const PProjectUnit& unit, mUnits) {
+        i++;
+        QByteArray groupName = toByteArray(QString("Unit%1").arg(i));
         if (!unit->FileMissing()) {
             bool rd_only = false;
             if (unit->modified() && fileExists(unit->fileName())
@@ -642,7 +648,12 @@ bool Project::saveUnits()
     return true;
 }
 
-PProjectUnit Project::findUnitByFilename(const QString &filename)
+PProjectUnit Project::findUnitById(int id)
+{
+    return mUnits.value(id,PProjectUnit());
+}
+
+PProjectUnit Project::findUnit(const QString &filename)
 {
     foreach(PProjectUnit unit, mUnits) {
         if (QString::compare(unit->fileName(),filename, PATH_SENSITIVITY)==0)
@@ -651,11 +662,16 @@ PProjectUnit Project::findUnitByFilename(const QString &filename)
     return PProjectUnit();
 }
 
-void Project::associateEditor(Editor *editor)
+PProjectUnit Project::findUnit(const Editor *editor)
 {
     if (!editor)
-        return;
-    PProjectUnit unit = findUnitByFilename(editor->filename());
+        return PProjectUnit();
+    return findUnit(editor->filename());
+}
+
+void Project::associateEditor(Editor *editor)
+{
+    PProjectUnit unit = findUnit(editor);
     associateEditorToUnit(editor,unit);
 }
 
@@ -718,21 +734,16 @@ void Project::updateFolders()
 {
     mFolders.clear();
     updateFolderNode(mRootNode);
-    for (int idx = 0; idx < mUnits.count();idx++)
-        mUnits[idx]->setFolder(
-                    getFolderPath(
-                        mUnits[idx]->node()->parent.lock()
+    foreach (PProjectUnit unit, mUnits) {
+        unit->setFolder(
+                    getNodePath(
+                        unit->node()->parent.lock()
                         )
                     );
+    }
     setModified(true);
 }
 
-void Project::updateNodeIndexes()
-{
-    for (int idx = 0;idx<mUnits.count();idx++)
-        mUnits[idx]->node()->unitIndex = idx;
-}
-
 PProjectModelNode Project::pointerToNode(ProjectModelNode *p, PProjectModelNode parent)
 {
     if (!p)
@@ -906,8 +917,8 @@ bool Project::saveAsTemplate(const QString &templateFolder,
     if (mOptions.modelType!=ProjectModelType::FileSystem)
         ini->SetLongValue("Project", "ModelType", (int)mOptions.modelType);
 
-    for (int i=0;i<mUnits.count();i++) {
-        const PProjectUnit& unit=mUnits[i];
+    int i=0;
+    foreach (const PProjectUnit &unit, mUnits) {
         QString unitName = extractFileName(unit->fileName());
         QByteArray section = toByteArray(QString("Unit%1").arg(i));
         if (!copyFile(unit->fileName(), dir.absoluteFilePath(unitName),true)) {
@@ -936,6 +947,7 @@ bool Project::saveAsTemplate(const QString &templateFolder,
             ini->SetValue(section,"Source", unitName.toUtf8());
             ini->SetValue(section,"Target", unitName.toUtf8());
         }
+        i++;
     }
     ini->SetLongValue("Project","UnitCount",mUnits.count());
     if (ini->SaveFile(fileName.toLocal8Bit())!=SI_OK) {
@@ -1066,10 +1078,13 @@ PProjectUnit Project::addUnit(const QString &inFileName, PProjectModelNode paren
     } else {
         newUnit->setEncoding(options().encoding.toUtf8());
     }
-    newUnit->setFolder(getFolderPath(parentNode));
-    newUnit->setNode(makeNewFileNode(extractFileName(newUnit->fileName()), false, parentNode));
-    newUnit->node()->unitIndex = mUnits.count();
-    mUnits.append(newUnit);
+    newUnit->setFolder(getNodePath(parentNode));
+    PProjectModelNode node = makeNewFileNode(extractFileName(newUnit->fileName()),
+                                             newUnit->id(),
+                                             newUnit->priority(), parentNode);
+    node->unitIndex = newUnit->id();
+    newUnit->setNode(node);
+    mUnits.insert(newUnit->id(),newUnit);
 
   // Determine compilation flags
     switch(getFileType(inFileName)) {
@@ -1436,12 +1451,11 @@ void Project::checkProjectFileForUpdate(SimpleIni &ini)
                     QMessageBox::Ok);
 }
 
-void Project::closeUnit(int index)
+void Project::closeUnit(int id)
 {
-    PProjectUnit unit = mUnits[index];
+    PProjectUnit unit = findUnitById(id);
     Editor * editor =unitEditor(unit);
     if (editor) {
-        saveUnitLayout(editor,index);
         editor->setInProject(false);
         mEditorList->forceCloseEditor(editor);
     }
@@ -1460,14 +1474,14 @@ void Project::createFolderNodes()
                     findnode = node->children[c];
             }
             if (!findnode)
-                node = makeNewFileNode(s.mid(0,i),true,node);
+                node = makeNewFolderNode(s.mid(0,i),node);
             else
                 node = findnode;
             node->unitIndex = -1;
             s.remove(0,i+1);
             i = s.indexOf('/');
         }
-        node = makeNewFileNode(s, true, node);
+        node = makeNewFolderNode(s, node);
         node->unitIndex = -1;
         mFolderNodes.append(node);
     }
@@ -1488,8 +1502,8 @@ void Project::createFileSystemFolderNodes()
     QSet<QString> headerFolders;
     QSet<QString> sourceFolders;
     QSet<QString> otherFolders;
-    for (int idx=0;idx<mUnits.count();idx++) {
-        QFileInfo fileInfo(mUnits[idx]->fileName());
+    foreach (const PProjectUnit& unit, mUnits) {
+        QFileInfo fileInfo(unit->fileName());
         if (isHFile(fileInfo.fileName())) {
             addFolderRecursively(headerFolders,fileInfo.absolutePath());
         } else if (isCFile(fileInfo.fileName())) {
@@ -1498,23 +1512,26 @@ void Project::createFileSystemFolderNodes()
             addFolderRecursively(otherFolders,fileInfo.absolutePath());
         }
     }
-    PProjectModelNode node = makeNewFileNode(tr("Headers"),true,mRootNode);
-    node->folderNodeType = ProjectModelNodeType::DUMMY_HEADERS_FOLDER;
-    node->priority = 1000;
+    PProjectModelNode node = makeNewFolderNode(tr("Headers"),
+                                               mRootNode,
+                                               ProjectModelNodeType::DUMMY_HEADERS_FOLDER,
+                                               1000);
     createFileSystemFolderNode(ProjectModelNodeType::DUMMY_HEADERS_FOLDER,folder(),node, headerFolders);
     mFolderNodes.append(node);
     mSpecialNodes.insert(ProjectModelNodeType::DUMMY_HEADERS_FOLDER,node);
 
-    node = makeNewFileNode(tr("Sources"),true,mRootNode);
-    node->folderNodeType = ProjectModelNodeType::DUMMY_SOURCES_FOLDER;
-    node->priority = 900;
+    node = makeNewFolderNode(tr("Sources"),
+                             mRootNode,
+                             ProjectModelNodeType::DUMMY_SOURCES_FOLDER,
+                             900);
     createFileSystemFolderNode(ProjectModelNodeType::DUMMY_SOURCES_FOLDER,folder(),node, sourceFolders);
     mFolderNodes.append(node);
     mSpecialNodes.insert(ProjectModelNodeType::DUMMY_SOURCES_FOLDER,node);
 
-    node = makeNewFileNode(tr("Others"),true,mRootNode);
-    node->folderNodeType = ProjectModelNodeType::DUMMY_OTHERS_FOLDER;
-    node->priority = 800;
+    node = makeNewFolderNode(tr("Others"),
+                             mRootNode,
+                             ProjectModelNodeType::DUMMY_OTHERS_FOLDER,
+                             800);
     createFileSystemFolderNode(ProjectModelNodeType::DUMMY_OTHERS_FOLDER,folder(),node, otherFolders);
     mFolderNodes.append(node);
     mSpecialNodes.insert(ProjectModelNodeType::DUMMY_OTHERS_FOLDER,node);
@@ -1533,7 +1550,7 @@ void Project::createFileSystemFolderNode(
         if (fileInfo.isHidden() || fileInfo.fileName().startsWith('.'))
             continue;
         if (fileInfo.isDir() && validFolders.contains(fileInfo.absoluteFilePath())) {
-            PProjectModelNode node = makeNewFileNode(fileInfo.fileName(),true,parent);
+            PProjectModelNode node = makeNewFolderNode(fileInfo.fileName(),parent);
             mFileSystemFolderNodes.insert(QString("%1/%2").arg((int)folderType).arg(fileInfo.absoluteFilePath()),node);
             createFileSystemFolderNode(folderType,fileInfo.absoluteFilePath(), node, validFolders);
         }
@@ -1575,7 +1592,7 @@ PProjectModelNode Project::folderNodeFromName(const QString &name)
     return mRootNode;
 }
 
-QString Project::getFolderPath(PProjectModelNode node)
+QString Project::getNodePath(PProjectModelNode node)
 {
     QString result;
     if (!node)
@@ -1597,7 +1614,7 @@ QString Project::getFolderPath(PProjectModelNode node)
 
 int Project::getUnitFromString(const QString &s)
 {
-    return indexInUnits(s);
+    return findUnitId(s);
 }
 
 PProjectModelNode Project::getParentFolderNode(const QString &filename)
@@ -1651,8 +1668,9 @@ void Project::loadLayout()
             openUnit(currIdx);
         }
     }
-    if (topLeft>=0 && topLeft<mUnits.count()) {
-        Editor * editor = unitEditor(mUnits[topLeft]);
+    PProjectUnit unit = findUnitById(topLeft);
+    if (unit) {
+        Editor * editor = unitEditor(unit);
         if (editor)
             editor->activate();
     }
@@ -1919,22 +1937,21 @@ PCppParser Project::cppParser()
     return mParser;
 }
 
-int Project::indexInUnits(const QString &fileName) const
+int Project::findUnitId(const QString &fileName) const
 {
     QDir dir(directory());
-    for (int i=0;i<mUnits.count();i++) {
-        PProjectUnit unit = mUnits[i];
+    foreach (const PProjectUnit& unit, mUnits) {
         if (dir.absoluteFilePath(fileName) == dir.absoluteFilePath(unit->fileName()))
-            return i;
+            return unit->id();
     }
     return -1;
 }
 
-int Project::indexInUnits(const Editor *editor) const
+int Project::findUnitId(const Editor *editor) const
 {
     if (!editor)
         return -1;
-    return indexInUnits(editor->filename());
+    return findUnitId(editor->filename());
 }
 
 void Project::removeFolderRecurse(PProjectModelNode node)
@@ -1967,7 +1984,7 @@ void Project::updateFolderNode(PProjectModelNode node)
     for (int i=0;i<node->children.count();i++){
         PProjectModelNode child = node->children[i];
         if (child->unitIndex<0) {
-            mFolders.append(getFolderPath(child));
+            mFolders.append(getNodePath(child));
             updateFolderNode(child);
         }
     }
@@ -2020,11 +2037,6 @@ EditorList *Project::editorList() const
     return mEditorList;
 }
 
-const QList<PProjectUnit> &Project::units() const
-{
-    return mUnits;
-}
-
 ProjectModelType Project::modelType() const
 {
     return mOptions.modelType;
@@ -2072,11 +2084,15 @@ const QString &Project::filename() const
     return mFilename;
 }
 
+int ProjectUnit::mIdGenerator=0;
+
 ProjectUnit::ProjectUnit(Project* parent)
 {
     mNode = nullptr;
     mParent = parent;
     mFileMissing = false;
+    mId=mIdGenerator++;
+    mPriority=0;
 }
 
 Project *ProjectUnit::parent() const
@@ -2270,6 +2286,16 @@ void ProjectUnit::setFileMissing(bool newDontSave)
     mFileMissing = newDontSave;
 }
 
+int ProjectUnit::id() const
+{
+    return mId;
+}
+
+void ProjectUnit::setId(int newId)
+{
+    mId = newId;
+}
+
 ProjectModel::ProjectModel(Project *project, QObject *parent):
     QAbstractItemModel(parent),
     mProject(project)
@@ -2305,6 +2331,23 @@ CustomFileIconProvider *ProjectModel::iconProvider() const
     return mIconProvider;
 }
 
+bool ProjectModel::insertRows(int row, int count, const QModelIndex &parent)
+{
+    qDebug()<<"insert rows";
+    qDebug()<<rowCount(parent);
+    beginInsertRows(parent,row,row+count-1);
+    endInsertRows();
+    return true;
+}
+
+bool ProjectModel::removeRows(int row, int count, const QModelIndex &parent)
+{
+    qDebug()<<"remove rows";
+    beginRemoveRows(parent,row,row+count-1);
+    endRemoveRows();
+    return true;
+}
+
 Project *ProjectModel::project() const
 {
     return mProject;
@@ -2370,7 +2413,7 @@ QVariant ProjectModel::data(const QModelIndex &index, int role) const
     } else if (role == Qt::DecorationRole) {
         QIcon icon;
         if (p->unitIndex>=0) {
-            icon = mIconProvider->icon(mProject->units()[p->unitIndex]->fileName());
+            icon = mIconProvider->icon(mProject->findUnitById(p->unitIndex)->fileName());
         } else {
             if (p == mProject->rootNode().get()) {
                 QString branch;
@@ -2440,7 +2483,7 @@ bool ProjectModel::setData(const QModelIndex &index, const QVariant &value, int
         int idx = node->unitIndex;
         if (idx >= 0) {
             //change unit name
-            PProjectUnit unit = mProject->units()[idx];
+            PProjectUnit unit = mProject->findUnitById(idx);
             QString newName = value.toString().trimmed();
             if (newName.isEmpty())
                 return false;
@@ -2464,7 +2507,7 @@ bool ProjectModel::setData(const QModelIndex &index, const QVariant &value, int
                         mProject->editorList()->closeEditor(e);
 
                     // Remove it from the current project...
-                    int projindex = mProject->indexInUnits(newName);
+                    int projindex = mProject->findUnitId(newName);
                     if (projindex>=0) {
                         mProject->removeUnit(projindex,false);
                     }
@@ -2496,7 +2539,7 @@ bool ProjectModel::setData(const QModelIndex &index, const QVariant &value, int
                                       QMessageBox::Ok);
                 return false;
             }
-            mProject->saveUnitAs(idx,newName);
+            mProject->renameUnit(idx,newName);
 
             // Add new filename to file minitor
             mProject->fileSystemWatcher()->addPath(newName);
@@ -2528,9 +2571,11 @@ bool ProjectModel::setData(const QModelIndex &index, const QVariant &value, int
 
 QModelIndex ProjectModel::getNodeIndex(ProjectModelNode *node) const
 {
+    if (!node)
+        return QModelIndex();
     PProjectModelNode parent = node->parent.lock();
     if (!parent) // root node
-        return QModelIndex();
+        return createIndex(0,0,node);
     int row = -1;
     for (int i=0;i<parent->children.count();i++) {
         const PProjectModelNode& pNode=parent->children[i];
@@ -2648,8 +2693,8 @@ bool ProjectModel::dropMimeData(const QMimeData *data, Qt::DropAction action, in
         droppedNode->parent = node;
         node->children.append(droppedNode);
         if (droppedNode->unitIndex>=0) {
-            PProjectUnit unit = mProject->units()[droppedNode->unitIndex];
-            unit->setFolder(mProject->getFolderPath(node));
+            PProjectUnit unit = mProject->findUnitById(droppedNode->unitIndex);
+            unit->setFolder(mProject->getNodePath(node));
         }
         QModelIndex newParentIndex = getParentIndex(droppedPointer);
         beginInsertRows(newParentIndex,node->children.count()-1,node->children.count()-1);
@@ -2678,7 +2723,7 @@ QMimeData *ProjectModel::mimeData(const QModelIndexList &indexes) const
         stream << (qint32)((*it).row()) << (qint32)((*it).column()) << (quintptr)((*it).internalPointer());
         ProjectModelNode* p = static_cast<ProjectModelNode*>((*it).internalPointer());
         if (p && p->unitIndex>=0) {
-            urls.append(QUrl::fromLocalFile(mProject->units()[p->unitIndex]->fileName()));
+            urls.append(QUrl::fromLocalFile(mProject->findUnitById(p->unitIndex)->fileName()));
         }
     }
     if (!urls.isEmpty())
diff --git a/RedPandaIDE/project.h b/RedPandaIDE/project.h
index cdfe19cb..ece8e176 100644
--- a/RedPandaIDE/project.h
+++ b/RedPandaIDE/project.h
@@ -18,6 +18,8 @@
 #define PROJECT_H
 
 #include <QAbstractItemModel>
+#include <QHash>
+#include <QSet>
 #include <QSortFilterProxyModel>
 #include <memory>
 #include "projectoptions.h"
@@ -37,6 +39,11 @@ enum ProjectModelNodeType {
     File
 };
 
+struct ProjectModelItemRecord {
+    ProjectModelNodeType type;
+    QString fullPath;
+};
+
 struct ProjectModelNode;
 using PProjectModelNode = std::shared_ptr<ProjectModelNode>;
 struct ProjectModelNode {
@@ -85,6 +92,10 @@ public:
     bool FileMissing() const;
     void setFileMissing(bool newDontSave);
 
+    int id() const;
+
+    void setId(int newId);
+
 private:
     Project* mParent;
     QString mFileName;
@@ -99,6 +110,8 @@ private:
     QByteArray mEncoding;
     PProjectModelNode mNode;
     bool mFileMissing;
+    int mId;
+    static int mIdGenerator;
 };
 
 using PProjectUnit = std::shared_ptr<ProjectUnit>;
@@ -129,9 +142,9 @@ public:
     bool setData(const QModelIndex &index, const QVariant &value, int role) override;
 
     QModelIndex getNodeIndex(ProjectModelNode *node) const;
+    QModelIndex getParentIndex(ProjectModelNode * node) const;
 
 private:
-    QModelIndex getParentIndex(ProjectModelNode * node) const;
 
     // QAbstractItemModel interface
 public:
@@ -141,6 +154,11 @@ public:
     QMimeData *mimeData(const QModelIndexList &indexes) const override;
     Project *project() const;
     CustomFileIconProvider *iconProvider() const;
+
+    // QAbstractItemModel interface
+public:
+    bool insertRows(int row, int count, const QModelIndex &parent) override;
+    bool removeRows(int row, int count, const QModelIndex &parent) override;
 };
 
 class ProjectModelSortFilterProxy : public QSortFilterProxyModel
@@ -177,44 +195,51 @@ public:
                 bool rebuild);
     QString folder();
     void buildPrivateResource(bool forceSave=false);
-    void closeUnit(int index);
+    void closeUnit(int id);
     void doAutoOpen();
     bool fileAlreadyExists(const QString& s);
 
-    QString getFolderPath(PProjectModelNode node);
+    QString getNodePath(PProjectModelNode node);
     int getUnitFromString(const QString& s);
     void incrementBuildNumber();
-    int indexInUnits(const QString& fileName) const;
-    int indexInUnits(const Editor* editor) const;
+
     PProjectUnit  newUnit(PProjectModelNode parentNode,
                  const QString& customFileName="");
     Editor* openUnit(int index, bool forceOpen=true);
     Editor* unitEditor(const PProjectUnit& unit) const;
     Editor* unitEditor(const ProjectUnit* unit) const;
-    Editor* unitEditor(int index) const {
-        if (index<0 || index>=mUnits.count())
+    Editor* unitEditor(int id) const {
+        PProjectUnit unit=mUnits.value(id,PProjectUnit());
+        if (!unit)
             return nullptr;
-        return unitEditor(mUnits[index]);
+        return unitEditor(unit);
     }
+
+    QList<PProjectUnit> unitList();
+
     PProjectModelNode pointerToNode(ProjectModelNode * p, PProjectModelNode parent=PProjectModelNode());
     void rebuildNodes();
-    bool removeUnit(int index, bool doClose, bool removeFile = false);
+    bool removeUnit(int id, bool doClose, bool removeFile = false);
     bool removeFolder(PProjectModelNode node);
     void resetParserProjectFiles();
     void saveAll(); // save [Project] and  all [UnitX]
     void saveLayout(); // save all [UnitX]
     void saveOptions();
-    void saveUnitAs(int i, const QString& sFileName, bool syncEditor = true); // save single [UnitX]
+    void renameUnit(int idx, const QString& sFileName);
     bool saveUnits();
 
-    PProjectUnit findUnitByFilename(const QString& filename);
+    PProjectUnit findUnitById(int id);
+    PProjectUnit findUnit(const QString& filename);
+    PProjectUnit findUnit(const Editor* editor);
+
+    int findUnitId(const QString& fileName) const;
+    int findUnitId(const Editor* editor) const;
     void associateEditor(Editor* editor);
     void associateEditorToUnit(Editor* editor, PProjectUnit unit);
     bool setCompileOption(const QString &key, const QString &value);
     QString getCompileOption(const QString &key) const;
 
     void updateFolders();
-    void updateNodeIndexes();
     void setCompilerSet(int compilerSetIndex);
 
     bool assignTemplate(const std::shared_ptr<ProjectTemplate> aTemplate, bool useCpp);
@@ -235,8 +260,6 @@ public:
 
     ProjectModel* model() ;
 
-    const QList<PProjectUnit> &units() const;
-
     ProjectModelType modelType() const;
     void setModelType(ProjectModelType type);
 
@@ -263,16 +286,24 @@ private:
     void loadLayout(); // load all [UnitX]
     void loadUnitLayout(Editor *e, int index); // load single [UnitX] cursor positions
 
-    PProjectModelNode makeNewFileNode(const QString& s, bool isFolder, PProjectModelNode newParent);
+    PProjectModelNode makeNewFolderNode(
+            const QString& folderName,
+            PProjectModelNode newParent,
+            ProjectModelNodeType nodeType=ProjectModelNodeType::Folder,
+            int priority=0);
+    PProjectModelNode makeNewFileNode(
+            const QString& fileName,
+            int unitId,
+            int priority,
+            PProjectModelNode newParent);
     PProjectModelNode makeProjectNode();
     void open();
     void removeFolderRecurse(PProjectModelNode node);
-    void saveUnitLayout(Editor* e, int index); // save single [UnitX] cursor positions
     void updateFolderNode(PProjectModelNode node);
     void updateCompilerSetType();
 
 private:
-    QList<PProjectUnit> mUnits;
+    QHash<int,PProjectUnit> mUnits;
     ProjectOptions mOptions;
     QString mFilename;
     QString mName;
diff --git a/RedPandaIDE/settingsdialog/projectfileswidget.cpp b/RedPandaIDE/settingsdialog/projectfileswidget.cpp
index 3039b698..494b2db1 100644
--- a/RedPandaIDE/settingsdialog/projectfileswidget.cpp
+++ b/RedPandaIDE/settingsdialog/projectfileswidget.cpp
@@ -47,7 +47,7 @@ void ProjectFilesWidget::doSave()
 {
     for (int i=0;i<mUnits.count();i++) {
         PProjectUnit unitCopy = mUnits[i];
-        PProjectUnit unit = pMainWindow->project()->units()[i];
+        PProjectUnit unit = pMainWindow->project()->findUnitById(unitCopy->id());
         unit->setPriority(unitCopy->priority());
         unit->setCompile(unitCopy->compile());
         unit->setLink(unitCopy->link());
@@ -70,11 +70,14 @@ PProjectUnit ProjectFilesWidget::currentUnit()
     ProjectModelNode* node = static_cast<ProjectModelNode*>(index.internalPointer());
     if (!node)
         return PProjectUnit();
-    int i = node->unitIndex;
-    if (i>=0) {
-        return mUnits[i];
-    } else
-        return PProjectUnit();
+    int idx = node->unitIndex;
+    if (idx>=0) {
+        foreach (PProjectUnit unit, mUnits) {
+            if (unit->id() == idx)
+                return unit;
+        }
+    }
+    return PProjectUnit();
 }
 
 void ProjectFilesWidget::copyUnits()
@@ -83,8 +86,9 @@ void ProjectFilesWidget::copyUnits()
     if (!project)
         return;
     mUnits.clear();
-    foreach (const PProjectUnit& unit, project->units()) {
+    foreach (const PProjectUnit& unit, project->unitList()) {
         PProjectUnit unitCopy = std::make_shared<ProjectUnit>(project.get());
+        unitCopy->setId(unit->id());
         unitCopy->setPriority(unit->priority());
         unitCopy->setCompile(unit->compile());
         unitCopy->setLink(unit->link());
diff --git a/RedPandaIDE/settingsdialog/projectgeneralwidget.cpp b/RedPandaIDE/settingsdialog/projectgeneralwidget.cpp
index 8276127a..9401dd8e 100644
--- a/RedPandaIDE/settingsdialog/projectgeneralwidget.cpp
+++ b/RedPandaIDE/settingsdialog/projectgeneralwidget.cpp
@@ -57,7 +57,7 @@ void ProjectGeneralWidget::doLoad()
     ui->txtOutputFile->setText(project->executable());
 
     int srcCount=0,headerCount=0,resCount=0,otherCount=0, totalCount=0;
-    foreach (const PProjectUnit& unit, project->units()) {
+    foreach (const PProjectUnit& unit, project->unitList()) {
         switch(getFileType(unit->fileName())) {
         case FileType::CSource:
         case FileType::CppSource:
diff --git a/RedPandaIDE/widgets/searchdialog.cpp b/RedPandaIDE/widgets/searchdialog.cpp
index c7a3de25..e9a70beb 100644
--- a/RedPandaIDE/widgets/searchdialog.cpp
+++ b/RedPandaIDE/widgets/searchdialog.cpp
@@ -362,9 +362,9 @@ void SearchDialog::on_btnExecute_clicked()
                         mSearchOptions,
                         SearchFileScope::wholeProject
                         );
-            for (int i=0;i<pMainWindow->project()->units().count();i++) {
-                Editor * e = pMainWindow->project()->unitEditor(i);
-                QString curFilename =  pMainWindow->project()->units()[i]->fileName();
+            foreach (PProjectUnit unit, pMainWindow->project()->unitList()) {
+                Editor * e = pMainWindow->project()->unitEditor(unit);
+                QString curFilename =  unit->fileName();
                 if (e) {
                     fileSearched++;
                     PSearchResultTreeItem parentItem = batchFindInEditor(