Qt6 port:

* Explicitly include some missing headers
* Use 'static const char*' for XPM icon
* Skip template parameters for qMakePair
* Constructor of QFileInfo is marked as 'explicit' now
* QString::fromLatin1() also accepts a QByteArray
* QDateTime::fromTime_t() is deprecated in Qt5 and has been removed in Qt6. Use QDateTime::fromSecsSinceEpoch()
* QDateTime::toTime_t() is deprecated in Qt5 and has been removed in Qt6. Use QDateTime::toSecsSinceEpoch()
* QApplication::globalStrut() is deprecated. Don't use it any more.
* QWidget::isTopLevel() is deprecated, use QWidget::isWindow()

src/Gui/View3DInventor.cpp

@@ -872,7 +872,7 @@ void View3DInventor::windowStateChanged(MDIView* view)
         // must be hidden, hence we can start the timer.
         // Note: If view is top-level or fullscreen it doesn't necessarily hide the other view
         // e.g. if it is on a second monitor.
-        canStartTimer = (!this->isTopLevel() && !view->isTopLevel() && view->isMaximized());
+        canStartTimer = (!this->isWindow() && !view->isWindow() && view->isMaximized());
     } else if (isMinimized()) {
         // I am the active view but minimized
         canStartTimer = true;