[mutter] events: Only support super+scroll on wayland

[Marge Bot <marge-bot src gnome org>]

commit 357c506ee75c15358c4c68827ae384d68ec2e69f
Author: Florian Müllner <fmuellner gnome org>
Date:   Wed Jul 7 22:40:33 2021 +0200

    events: Only support super+scroll on wayland
    
    On Xorg, the event only reaches us when the pointer is within the
    stage input region. That makes the feature more confusing than
    useful, so make it wayland-only.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/3759
    
    Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1922>

 src/core/events.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
---
diff --git a/src/core/events.c b/src/core/events.c
index 92fb602c7e..8afc720efd 100644
--- a/src/core/events.c
+++ b/src/core/events.c
@@ -373,7 +373,9 @@ meta_display_handle_event (MetaDisplay        *display,
         }
     }
 
-  if (event->type == CLUTTER_SCROLL && meta_prefs_get_mouse_button_mods () > 0)
+  if (meta_is_wayland_compositor () &&
+      event->type == CLUTTER_SCROLL &&
+      meta_prefs_get_mouse_button_mods () > 0)
     {
       ClutterModifierType grab_mods;