increased size of color patch
see: https://bugs.freedesktop.org/show_bug.cgi?id=78825 Ideally the patch size would be something like "biggest of either 400px or 80% of shortest display size" or even better: "size = shortest of display height - button height plus progress bar height OR display width". But as I have no knowledge of gtk, easiest improvement seems to just increase the patch size a little. I believe most screens used today will at least have 1024x768px, thus 600x600 should be fine.