All Qt dialogs used by Avidemux have an unused "?" button in the titlebar. It should be disabled with QtCore.Qt.WindowContextHelpButtonHint
(https://i.stack.imgur.com/CSLnm.png)
https://stackoverflow.com/questions/16087442/remove-whatsthis-from-a-dialog-in-pyside
Edit: Solved in r210228 v2.7.7
Thanks, looks like it is Windows-only starting with Qt 5.10. Neither Linux with gnome-shell nor macOS are affected. Qt documentation states that the ? button isn't added by default in Qt 6.x.
Much more bothering is keyboard events being registered by the main window while the script console is open, at least on macOS. Getting tired of the Go menu flicker when using arrow keys in the console.