Some labels fail to reveal mnemonic underlines when Alt is pressed (again?)
e.g. run gtk4-widget-factory
and go to Page 2, press Alt, see no underlines appearing on the menu bar's items (but the mnemonic keys DO work to open the menus).
I have also seen this with (some, but not all) Labels acting as mnemonic-widgets for buttons in one of my projects.
I've seen #4818 (closed) et al., but I have Pango 1.50.14, so I'm unsure if that can be the cause.
Edited by Daniel Boles