fix: dark/light theme's combobox dropdown list display error

RedPandaIDE/themes/dark/style.qss

@@ -1227,7 +1227,9 @@ QComboBox {
   /* padding-right = 36; 4 + 16*2 See scrollbar size */
   /* changed to 4px to fix #239 */
   /* Fixes #103, #111 */
+  /*
   min-height: 1.5em;
+  */
   /* padding-top: 2px;     removed to fix #132 */
   /* padding-bottom: 2px;  removed to fix #132 */
   /* min-width: 75px;      removed to fix #109 */
@@ -1247,7 +1249,7 @@ QComboBox QAbstractItemView:hover {
 }
 
 QComboBox QAbstractItemView:selected {
-  background: #346792;
+  background-color: #346792;
   color: #455364;
 }
 
@@ -1290,9 +1292,11 @@ QComboBox::item:alternate {
   background: #19232D;
 }
 
+/*
 QComboBox::item:checked {
   font-weight: bold;
 }
+*/
 
 QComboBox::item:selected {
   border: 0px solid transparent;

RedPandaIDE/themes/light/style.qss

@@ -1290,9 +1290,11 @@ QComboBox::item:alternate {
   background: #FAFAFA;
 }
 
+/*
 QComboBox::item:checked {
   font-weight: bold;
 }
+*/
 
 QComboBox::item:selected {
   border: 0px solid transparent;

RedPandaIDE/utils.cpp

@@ -417,17 +417,23 @@ void changeTheme(const QString &themeName)
 {
     if (themeName.isEmpty() || themeName == "default") {
         QApplication::setStyle("Fusion");
+        QApplication* app = dynamic_cast<QApplication*>(QApplication::instance());
+        app->setStyleSheet("");
         return ;
     }
     QStyleFactory styleFactory;
     if (styleFactory.keys().contains(themeName)) {
         QApplication::setStyle(themeName);
+        QApplication* app = dynamic_cast<QApplication*>(QApplication::instance());
+        app->setStyleSheet("");
+        return;
     }
     QFile f(QString(":/themes/%1/style.qss").arg(themeName));
 
     if (!f.exists())   {
         qDebug()<<"Unable to set stylesheet, file not found\n";
     } else {
+        QApplication::setStyle("fusion");
         f.open(QFile::ReadOnly | QFile::Text);
         QTextStream ts(&f);
         dynamic_cast<QApplication*>(QApplication::instance())->setStyleSheet(ts.readAll());