How to forcefully kill a hanging application started by the App Designer without killing the App Designer itself?

While developing a GUI application with the App Designer my application hangs from time to time because of bugs. However I can't find any way to forcefully kill this GUI application other than through the activity monitor (I'm on Mac OS) which also always kills the whole App Designer. I'm sure I missed something obvious here because killing an application during development without killing the "IDE" seems like a quite usual thing to me. I know that I can always kill a running matlab script with cmd + c, so I am looking for a similar thing for the GUI application.

Thank you for your help in advance!