DnD hotspot doesn't work with Wayland+GL
gdk_wayland_drag_set_hotspot()
calls _gdk_wayland_surface_offset_next_wl_buffer()
and sets pending_buffer_offset_x/y
values which will be applied on the next gdk_wayland_surface_attach_image()
call. However, gdk_wayland_surface_attach_image()
is only called with Cairo renderer.
It can be reproduced in the gtk4-demo -> Drag-and-Drop as follows:
X11:
Wayland/Cairo:
Wayland/GL: