diff --git a/NEWS.md b/NEWS.md
index e2cc2885..31cc9dab 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -4,6 +4,7 @@ Red Panda C++ Version 1.0.0
   - enhancement: "locate in files view" will request user's confirmation when change the working folder
   - enhancement: adjust tab order in the find dialog
   - enhancement: highlight hits in the find panel's result list
+  - enhancement: optimize startup time
 
 Red Panda C++ Version 0.14.5
   - fix: the "gnu c++ 20" option in compiler set options is wrong
diff --git a/RedPandaIDE/main.cpp b/RedPandaIDE/main.cpp
index 7d3c83be..58a3cd62 100644
--- a/RedPandaIDE/main.cpp
+++ b/RedPandaIDE/main.cpp
@@ -249,7 +249,6 @@ int main(int argc, char *argv[])
 
     QApplication app(argc, argv);
     QFile tempFile(QDir::tempPath()+QDir::separator()+"RedPandaDevCppStartUp.lock");
-
     {
         bool firstRun;
         QString settingFilename = getSettingFilename(QString(), firstRun);
@@ -354,6 +353,13 @@ int main(int argc, char *argv[])
 
         MainWindow mainWindow;
         pMainWindow = &mainWindow;
+#if QT_VERSION_MAJOR==5 && QT_VERSION_MINOR < 15
+        setScreenDPI(qApp->primaryScreen()->logicalDotsPerInch());
+#else
+        if (mainWindow.screen())
+            setScreenDPI(mainWindow.screen()->logicalDotsPerInch());
+#endif
+        mainWindow.show();
         if (app.arguments().count()>1) {
             QStringList filesToOpen = app.arguments();
             filesToOpen.pop_front();
@@ -365,22 +371,20 @@ int main(int argc, char *argv[])
                 pMainWindow->newEditor();
             }
         }
-#if QT_VERSION_MAJOR==5 && QT_VERSION_MINOR < 15
-        setScreenDPI(qApp->primaryScreen()->logicalDotsPerInch());
-#else
-        if (mainWindow.screen())
-            setScreenDPI(mainWindow.screen()->logicalDotsPerInch());
-#endif
-        mainWindow.show();
 
         //reset default open folder
         QDir::setCurrent(pSettings->environment().defaultOpenFolder());
 
+        pMainWindow->setFilesViewRoot(pSettings->environment().currentFolder());
+
 #ifdef Q_OS_WIN
         WindowLogoutEventFilter filter;
         app.installNativeEventFilter(&filter);
 #endif
-        tempFile.remove();
+        if (tempFile.isOpen()) {
+            tempFile.close();
+            tempFile.remove();
+        }
         int retCode = app.exec();
         QString configDir = pSettings->dirs().config();
         // save settings
diff --git a/RedPandaIDE/mainwindow.cpp b/RedPandaIDE/mainwindow.cpp
index 89a04783..437a188f 100644
--- a/RedPandaIDE/mainwindow.cpp
+++ b/RedPandaIDE/mainwindow.cpp
@@ -299,7 +299,7 @@ MainWindow::MainWindow(QWidget *parent)
 
     mFileSystemModel.setNameFilters(pSystemConsts->defaultFileNameFilters());
     mFileSystemModel.setNameFilterDisables(false);
-    setFilesViewRoot(pSettings->environment().currentFolder());
+    //setFilesViewRoot(pSettings->environment().currentFolder());
     for (int i=1;i<mFileSystemModel.columnCount();i++) {
         ui->treeFiles->hideColumn(i);
     }
@@ -674,7 +674,8 @@ void MainWindow::applySettings()
 
     //icon sets for files view
     pIconsManager->updateFileSystemIcons(pSettings->environment().iconSet(),pointToPixel(pSettings->environment().interfaceFontSize()));
-    setFilesViewRoot(mFileSystemModel.rootPath());
+    if (!mFileSystemModel.rootPath().isEmpty() && mFileSystemModel.rootPath()!=".")
+        setFilesViewRoot(pSettings->environment().currentFolder());
 //    for (int i=0;i<ui->cbFilesPath->count();i++) {
 //        ui->cbFilesPath->setItemIcon(i,pIconsManager->getIcon(IconsManager::FILESYSTEM_GIT));
 //    }
@@ -1205,8 +1206,8 @@ void MainWindow::updateCompilerSet()
 {
     mCompilerSet->blockSignals(true);
     mCompilerSet->clear();
-    for (size_t i=0;i<pSettings->compilerSets().list().size();i++) {
-        mCompilerSet->addItem(pSettings->compilerSets().list()[i]->name());
+    for (size_t i=0;i<pSettings->compilerSets().size();i++) {
+        mCompilerSet->addItem(pSettings->compilerSets().getSet(i)->name());
     }
     int index=pSettings->compilerSets().defaultIndex();
     if (mProject) {
diff --git a/RedPandaIDE/mainwindow.h b/RedPandaIDE/mainwindow.h
index e5bf6d48..cc52db18 100644
--- a/RedPandaIDE/mainwindow.h
+++ b/RedPandaIDE/mainwindow.h
@@ -120,6 +120,8 @@ public:
     void showSearchPanel(bool showReplace = false);
     void showCPUInfoDialog();
 
+    void setFilesViewRoot(const QString& path, bool setOpenFolder=false);
+
     void applySettings();
     void applyUISettings();
     QFileSystemWatcher* fileSystemWatcher();
@@ -243,7 +245,6 @@ private:
     void scanActiveProject(bool parse=false);
     void includeOrSkipDirs(const QStringList& dirs, bool skip);
     void showSearchReplacePanel(bool show);
-    void setFilesViewRoot(const QString& path, bool setOpenFolder=false);
     void clearIssues();
     void doCompileRun(RunType runType);
     void updateProblemCaseOutput(POJProblemCase problemCase);
diff --git a/RedPandaIDE/project.cpp b/RedPandaIDE/project.cpp
index 11488049..2016532a 100644
--- a/RedPandaIDE/project.cpp
+++ b/RedPandaIDE/project.cpp
@@ -631,7 +631,7 @@ void Project::setCompilerOption(const QString &optionString, char value)
     if (mOptions.compilerSet<0 || mOptions.compilerSet>=pSettings->compilerSets().size()) {
         return;
     }
-    std::shared_ptr<Settings::CompilerSet> compilerSet = pSettings->compilerSets().list()[mOptions.compilerSet];
+    std::shared_ptr<Settings::CompilerSet> compilerSet = pSettings->compilerSets().getSet(mOptions.compilerSet);
     int optionIndex = compilerSet->findOptionIndex(optionString);
     // Does the option exist?
     if (optionIndex>=0){
diff --git a/RedPandaIDE/settings.cpp b/RedPandaIDE/settings.cpp
index 3a340a5b..cd52c4fe 100644
--- a/RedPandaIDE/settings.cpp
+++ b/RedPandaIDE/settings.cpp
@@ -1442,6 +1442,10 @@ Settings::CompilerSet::CompilerSet(const QString& compilerFolder):
         setUserInput();
 
         setDefines();
+
+        mFullLoaded = true;
+    } else {
+        mFullLoaded = false;
     }
     setOptions();
 }
@@ -1468,7 +1472,8 @@ Settings::CompilerSet::CompilerSet(const Settings::CompilerSet &set):
     mUseCustomLinkParams(set.mUseCustomLinkParams),
     mCustomCompileParams(set.mCustomCompileParams),
     mCustomLinkParams(set.mCustomLinkParams),
-    mAutoAddCharsetParams(set.mAutoAddCharsetParams)
+    mAutoAddCharsetParams(set.mAutoAddCharsetParams),
+    mFullLoaded(set.mFullLoaded)
 {
     // Executables, most are hardcoded
     for (PCompilerOption pOption:set.mOptions) {
@@ -1738,16 +1743,31 @@ QStringList &Settings::CompilerSet::libDirs()
 
 QStringList &Settings::CompilerSet::defaultCIncludeDirs()
 {
+    if (!mFullLoaded && !binDirs().isEmpty()) {
+        mFullLoaded=true;
+        setDirectories(binDirs()[0]);
+        setDefines();
+    }
     return mDefaultCIncludeDirs;
 }
 
 QStringList &Settings::CompilerSet::defaultCppIncludeDirs()
 {
+    if (!mFullLoaded && !binDirs().isEmpty()) {
+        mFullLoaded=true;
+        setDirectories(binDirs()[0]);
+        setDefines();
+    }
     return mDefaultCppIncludeDirs;
 }
 
 QStringList &Settings::CompilerSet::defaultLibDirs()
 {
+    if (!mFullLoaded && !binDirs().isEmpty()) {
+        mFullLoaded=true;
+        setDirectories(binDirs()[0]);
+        setDefines();
+    }
     return mLibDirs;
 }
 
@@ -1791,8 +1811,13 @@ void Settings::CompilerSet::setName(const QString &value)
     mName = value;
 }
 
-const QStringList& Settings::CompilerSet::defines() const
+const QStringList& Settings::CompilerSet::defines()
 {
+    if (!mFullLoaded && !binDirs().isEmpty()) {
+        mFullLoaded=true;
+        setDirectories(binDirs()[0]);
+        setDefines();
+    }
     return mDefines;
 }
 
@@ -2724,11 +2749,6 @@ void Settings::CompilerSets::deleteSet(int index)
     saveSets();
 }
 
-Settings::CompilerSetList &Settings::CompilerSets::list()
-{
-    return mList;
-}
-
 int Settings::CompilerSets::size() const
 {
     return mList.size();
@@ -2901,8 +2921,9 @@ Settings::PCompilerSet Settings::CompilerSets::loadSet(int index)
 
     if (pSet->binDirs().isEmpty())
         return PCompilerSet();
-    pSet->setDirectories(pSet->binDirs()[0]);
-    pSet->setDefines();
+
+    //pSet->setDirectories(pSet->binDirs()[0]);
+    //pSet->setDefines();
     return pSet;
 }
 
diff --git a/RedPandaIDE/settings.h b/RedPandaIDE/settings.h
index 712c6d88..2d6e17e7 100644
--- a/RedPandaIDE/settings.h
+++ b/RedPandaIDE/settings.h
@@ -1210,7 +1210,7 @@ public:
         void setType(const QString& value);
         const QString& name() const;
         void setName(const QString& value);
-        const QStringList& defines() const;
+        const QStringList& defines();
         const QString& target() const;
         void setTarget(const QString& value);
 
@@ -1261,6 +1261,7 @@ public:
         QByteArray getCompilerOutput(const QString& binDir, const QString& binFile,
                                      const QStringList& arguments);
     private:
+        bool mFullLoaded;
         // Executables, most are hardcoded
         QString mCCompiler;
         QString mCppCompiler;
@@ -1320,8 +1321,6 @@ public:
         void saveDefaultIndex();
         void deleteSet(int index);
         void saveSet(int index);
-        //properties
-        CompilerSetList& list();
         int size() const;
         int defaultIndex() const;
         void setDefaultIndex(int value);
diff --git a/RedPandaIDE/settingsdialog/compilersetoptionwidget.cpp b/RedPandaIDE/settingsdialog/compilersetoptionwidget.cpp
index e3850d49..c3310fc9 100644
--- a/RedPandaIDE/settingsdialog/compilersetoptionwidget.cpp
+++ b/RedPandaIDE/settingsdialog/compilersetoptionwidget.cpp
@@ -167,7 +167,7 @@ void CompilerSetOptionWidget::doLoad()
 {
     disconnectInputs();
     ui->cbCompilerSet->clear();
-    if (pSettings->compilerSets().list().size()<=0) {
+    if (pSettings->compilerSets().size()<=0) {
         ui->btnRenameCompilerSet->setEnabled(false);
         ui->btnRemoveCompilerSet->setEnabled(false);
         return;
@@ -176,8 +176,8 @@ void CompilerSetOptionWidget::doLoad()
         ui->btnRemoveCompilerSet->setEnabled(true);
     }
     int index=pSettings->compilerSets().defaultIndex();
-    for (int i=0;i<pSettings->compilerSets().list().size();i++) {
-        ui->cbCompilerSet->addItem(pSettings->compilerSets().list()[i]->name());
+    for (int i=0;i<pSettings->compilerSets().size();i++) {
+        ui->cbCompilerSet->addItem(pSettings->compilerSets().getSet(i)->name());
     }
     if (index < 0 || index>=ui->cbCompilerSet->count()) {
         index = 0;
@@ -189,7 +189,7 @@ void CompilerSetOptionWidget::doLoad()
 
 void CompilerSetOptionWidget::doSave()
 {
-    if (pSettings->compilerSets().list().size()>0) {
+    if (pSettings->compilerSets().size()>0) {
         saveCurrentCompilerSet();
     }
     pSettings->compilerSets().saveSets();
@@ -296,7 +296,7 @@ void CompilerSetOptionWidget::on_btnAddBlankCompilerSet_pressed()
 {
     QString name = QInputDialog::getText(this,tr("Compiler Set Name"),tr("Name"));
     pSettings->compilerSets().addSet();
-    pSettings->compilerSets().setDefaultIndex(pSettings->compilerSets().list().size()-1);
+    pSettings->compilerSets().setDefaultIndex(pSettings->compilerSets().size()-1);
     pSettings->compilerSets().defaultSet()->setName(name);
     doLoad();
 }
diff --git a/RedPandaIDE/settingsdialog/projectcompilerwidget.cpp b/RedPandaIDE/settingsdialog/projectcompilerwidget.cpp
index 076a9de5..817b369b 100644
--- a/RedPandaIDE/settingsdialog/projectcompilerwidget.cpp
+++ b/RedPandaIDE/settingsdialog/projectcompilerwidget.cpp
@@ -145,8 +145,8 @@ void ProjectCompilerWidget::doSave()
 void ProjectCompilerWidget::init()
 {
     ui->cbCompilerSet->clear();
-    for (const Settings::PCompilerSet& set:pSettings->compilerSets().list()){
-        ui->cbCompilerSet->addItem(set->name());
+    for (int i=0;i<pSettings->compilerSets().size();i++) {
+        ui->cbCompilerSet->addItem(pSettings->compilerSets().getSet(i)->name());
     }
     SettingsWidget::init();
 }
diff --git a/RedPandaIDE/vcs/gitmanager.cpp b/RedPandaIDE/vcs/gitmanager.cpp
index 48e76915..109ecbdf 100644
--- a/RedPandaIDE/vcs/gitmanager.cpp
+++ b/RedPandaIDE/vcs/gitmanager.cpp
@@ -35,7 +35,8 @@ void GitManager::createRepository(const QString &folder)
 
 bool GitManager::hasRepository(const QString &folder, QString& currentBranch)
 {
-
+    if (folder.isEmpty())
+        return false;
     QStringList args;
     args.append("status");
     args.append("-b");
diff --git a/RedPandaIDE/vcs/gitrepository.cpp b/RedPandaIDE/vcs/gitrepository.cpp
index 353f3da9..fccb176f 100644
--- a/RedPandaIDE/vcs/gitrepository.cpp
+++ b/RedPandaIDE/vcs/gitrepository.cpp
@@ -77,13 +77,16 @@ bool GitRepository::revert(QString& output)
 void GitRepository::setFolder(const QString &newFolder)
 {
     mFolder = newFolder;
-    mRealFolder = mManager->rootFolder(mFolder);
+    if (!newFolder.isEmpty())
+        mRealFolder = mManager->rootFolder(mFolder);
+    else
+        mRealFolder = newFolder;
     update();
 }
 
 void GitRepository::update()
 {
-    if (!mManager->isValid()) {
+    if (!mManager->isValid() || mFolder.isEmpty()) {
         mInRepository = false;
         mBranch = "";
         mFilesInRepositories.clear();
diff --git a/RedPandaIDE/widgets/searchdialog.cpp b/RedPandaIDE/widgets/searchdialog.cpp
index 60f580cb..ad4417ad 100644
--- a/RedPandaIDE/widgets/searchdialog.cpp
+++ b/RedPandaIDE/widgets/searchdialog.cpp
@@ -60,6 +60,7 @@ void SearchDialog::find(const QString &text)
         mTabBar->setCurrentIndex(0);
     }
     ui->cbFind->setCurrentText(text);
+    ui->cbFind->setFocus();
     show();
 }
 
@@ -81,6 +82,7 @@ void SearchDialog::findInFiles(const QString &text)
 {
     mTabBar->setCurrentIndex(2);
     ui->cbFind->setCurrentText(text);
+    ui->cbFind->setFocus();
     show();
 }
 
@@ -89,6 +91,8 @@ void SearchDialog::findInFiles(const QString &keyword, SearchFileScope scope, Sy
     mTabBar->setCurrentIndex(1);
 
     ui->cbFind->setCurrentText(keyword);
+    ui->cbFind->setFocus();
+
     switch(scope) {
     case SearchFileScope::currentFile:
         ui->rbCurrentFile->setChecked(true);
@@ -114,6 +118,7 @@ void SearchDialog::replace(const QString &sFind, const QString &sReplace)
     mTabBar->setCurrentIndex(1);
     ui->cbFind->setCurrentText(sFind);
     ui->cbReplace->setCurrentText(sReplace);
+    ui->cbFind->setFocus();
     show();
 }