gdk/wayland: Fix button mask calculation on button events
There's 2 things broken here:
- The mask was calculated on top of the GDK button (i.e. skipping
4-7 buttons), so GDK_BUTTON4_MASK and GDK_BUTTON5_MASK were not
assigned. This is now calculated on the (continuous) BTN_ evcodes
so it is guaranteed that the next 2 physical buttons (i.e.
back/forward) get these two places in the mask assigned.
- Furthermore, these buttons would be pushed to places in the
modifier mask that they didn't belong to. It is now checked hard
that only the first 5 buttons enable a modifier flag.
Overall, this ensures that no event masks with bonkers values are
forwarded, and that no stale implicit grabs are left after additional
buttons are pressed.
Closes: https://gitlab.gnome.org/GNOME/gtk/-/issues/5301
projects / gtk4.git / commit