Fixed border issue with property pane tab

share/qtcreator/qmldesigner/propertyeditor/Qt/switch.css

@@ -12,7 +12,7 @@ QPushButton {
  }
  
   QPushButton:hover {
-     border: none; /* no border for a flat push button */
+     /*border: none;  no border for a flat push button */
 	 
 	background-color: qlineargradient(x1: 0, y1: 0, x2: 0, y2: 1,
                                        stop: 0 #3c3c3c, stop: 1 #666666);