requested to merge sophie-h/gtk:wip/sophie-h/scrolled-window-propagate-event into main
My issue: Images in GNOME are embedded in a ScrolledWindow for moving through the image when zoomed in. But if completely zoomed out, we want to swipe through the images and therefore need the events that ScrolledWindow does not propagate.
This patch propagates the signals whenever there are no visible scrollbars (i.e. nothing to scroll).
Related to #3446