Adds @gesture to the same group than @group_gesture.
Gestures are by default isolated in their own groups.
Both gestures must have been added to the same widget before
they can be grouped.
When gestures are grouped, the state of GdkEventSequences
is kept in sync for all of those, so calling
[method@Gtk.Gesture.set_sequence_state], on one will transfer
the same value to the others.
Groups also perform an "implicit grabbing" of sequences, if a
GdkEventSequence state is set to %GTK_EVENT_SEQUENCE_CLAIMED
on one group, every other gesture group attached to the same
GtkWidget will switch the state for that sequence to
%GTK_EVENT_SEQUENCE_DENIED.
Adds @gesture to the same group than @group_gesture.
Gestures are by default isolated in their own groups.
Both gestures must have been added to the same widget before they can be grouped.
When gestures are grouped, the state of GdkEventSequences is kept in sync for all of those, so calling [method@Gtk.Gesture.set_sequence_state], on one will transfer the same value to the others.
Groups also perform an "implicit grabbing" of sequences, if a GdkEventSequence state is set to %GTK_EVENT_SEQUENCE_CLAIMED on one group, every other gesture group attached to the same GtkWidget will switch the state for that sequence to %GTK_EVENT_SEQUENCE_DENIED.