Submitted by Jeff F.T.
Would be nice to have "pinch zoom" (to change the zoom level) and swiping (to scroll the timeline) at least. Specifically, GtkGestureZoom and GtkGestureSwipe are probably what we're looking for, among other things in https://developer.gnome.org/gtk3/stable/Gestures.html
For an introduction to gestures in GTK, see:
Imported from https://bugzilla.gnome.org/show_bug.cgi?id=703003