I posted this before in another topic, but I believe it
might have been buried and unseen.
This is a pretty big issue, and has not been fixed yet in the Alpha, or the pre-release build
of the editor.
Please check it out:
If you pick the brush, draw around a bit, (kind of quickly) then afterwards
hit ctrl+a (select all) then delete, (via del key) not all of your strokes will actually be erased, and you’ll be left with an un-eraseable blob of paint.
Attempting to use the brush after this will make it draw with that un-eraseable blob, creating a really funky looking pattern, which causes mega slow down.