I’m new to Qubes.
I repeatedly had the problem (with 4.2.3) that on the login screen (xfce) the selected keyboard layout doesn’t seem to be effective. The password was entered with French (France) but the pw is rejected, then I selected German (Germany) because I know the layout, no success. Then I had the idea to look at an English (USA) layout and type the corresponding keys. Despite still having the German layout selected, my password was accepted. Then I tried again with English (USA) selected and typing again according to English (USA), and again it let me in. So the menu doesn’t seem to have any effect.
If I lock the session, the displayed keyboard layout is correct.
On a side note, it would be really helpful to reduce the long menu of keyboard layouts to the ones that I installed, or make them at least searchable, or order them alphabetically by display name.