Thunderbird and Firefox overlap hidden taskbar

Firefox and Thunderbird when started maximized overlap hidden taskbar. Taskbar won’t show until Firefox/Thunderbird is minimized and maximized. Another way is to press the Win key two times to show a hidden taskbar. This happens only if taskbar is set to hide. Snapping to maximize also overlaps the hidden taskbar.

Is there a setting that can be changed to use Thunderbird and Firefox maximized and to not overlap hidden taskbar?

Windows 10. Firefox and Thunderbird any version. Latest Thunderbird version used.