Idea: Brush tip editor as a docker

In recent post I mentioned something similar that is on my ToDo list:

The part about using copied pixels in the clipboard to create new Brush Tip. Initially I imagined it similarly to @wojtryb mock-up, but docker is a possibility.

I was also thinking about making something like Tip Collections those would work like one Brush Tip but actually would be few separated Tips with some meta data file that allows to use them as a union. They could be then used to create, in simple manner, animated brushes either using each tip in a sequence, or randomly, or maybe other behaviors.

I will probably make feedback and brainstorm thread when I will be close to working on this.