Request: improvements to global selection mask

This is a nice set of suggestion and counter proposal for the earlier suggestion of brush selection tool . Good feature request :+1:

This does make global selection masks on par with what is expected in that request from the brush selection tool.

Thanks for making the thread. Let us see what people say about both.

I think probably it is better to tag @halla and @dkazakov on this just to inform them and also bring other two threads about the brush selection tool to their notice.