The XSizeHints set by X11 clients give a hint to the window manager
about size increment, aspect ratio, base, minimum and maximum size, etc.
When an X11 client changes those values, there is a good chance that it
will affect the actual window size in some way, and mutter rightfully
queue a window resize in that case.
However, mutter does not check if any of the hints have actually changed
and unconditionally queue a window resize whenever a client changes its
WM_NORMAL_HINTS property.
That can be a problem when a zealous client such as xterm decides to
update its WM_NORMAL_HINTS property on resize, because in return mutter
will queue a non-user driven resize in the middle of user-driven events,
hence defeating the purpose of the META_MOVE_RESIZE_USER_ACTION flag.
To avoid that issue, make mutter a bit smarter and avoid queuing a
window resize if the XSizeHints haven't actually changed.
https://gitlab.gnome.org/GNOME/mutter/-/issues/543
deaa9480a8