It is possible that more than one modifiers is configured as
"button modifier". While mutter should only let through
scroll events when all modifiers are present, it doesn't hurt
to check for it on the gnome-shell side as well.
Related: https://gitlab.gnome.org/GNOME/mutter/-/issues/4129
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/3725>
return false;
if (!this._began && this.scrollModifiers !== 0 &&
- (event.get_state() & this.scrollModifiers) === 0)
+ (event.get_state() & this.scrollModifiers) !== this.scrollModifiers)
return false;
return true;