Sorry I was watching "Rush" from Ron Howard... great movie, recommend!
Your drawing is nice!
And the moving selection now works but... how to stick the selection to background? XD
Seeing that you are so good at bugfixing, I report the last bug that, if fixed, could be a nice bonus for a pro-level software:
when zooming or using a too big canvas, scroll bars appear. The problem is that if you try to draw, when you move the cursor it also controls the scrollbars and make you go wrong. Putting a two finger shorcut for scroll gestures instead one only would improve the epicness of this port and allow to draw art masterpieces
The alternative is to just ignore one fingers taps for moving the canvas purposes, and let do it only by using directly the scrollbars, that are also more precise and allow continuous scroll
A three finger tap shortcut would be also useful to clean the canvas, so that rgbpaint can be used also as whiteboard... or a button that does the same, or both... Ok I've finished for real now ahah xD if only I would be able to do these things myself!