Ever since 2e00119, modifiers have been broken when trying to input characters like ^C with virtual keyboards like squeekboard or wvkbd.

All virtual keyboard implementations skip the on_keyboard_modifiers implementation, however I believe due to the changes made in this patch it is necessary to manually update the modifiers.

I have not been able to make this work without changing Smithay, at least partially due to the state() function on the XKB struct returning a non-mutable reference. I'm curious @Bot-wxt1221, did you test your implementation with modifiers? Do you have an implementation for your own compositor which is different from the broken implementation in Anvil?