When invoking QFileDialog::getExistingDirectory() directly in a QAction::triggered() slot (triggered via QMenu from a QMainWindow), the application crashes. However, deferring the call using QMetaObject::invokeMethod() with Qt::QueuedConnection prevents the crash.

The issue arises when showing a modal file dialog immediately in response to a context menu action.The crash does not happen when the call is deferred with Qt::QueuedConnection, or if the dialog is shown inside a lambda posted to the event loop.The QMainWindow is still valid, and no object is being deleted.
epro Steps:
 
Using attached example it can be easily seen:
 
Right-click to open a context menu in a QMainWindow.
Trigger a menu action that says "direct" 
Close the file dialog.
Application crashes.