Working on a 2-layer picture, with lots of dialogs open.
In Rainbow Painter nothing stops just because you open a few dialogs and menus.
You can even paint under them, as long as the stroke begins outside!
Note that you can scale down the size of a dialog or a menu with a simple click,
and it will still work just as well as before (only smaller).
The screenshot has been reduced in size to fit the page.