@Thomas E Jenkins: Thanks for the GDK_NATIVE_WINDOWS=1 workaround, I can confirm it fixes the problem for the Edit menu, Python-mode, SCLang-mode and Org-mode.
@Thomas E Jenkins: Thanks for the GDK_NATIVE_ WINDOWS= 1 workaround, I can confirm it fixes the problem for the Edit menu, Python-mode, SCLang-mode and Org-mode.