I have been exploring colour popping in AP using the paint brush, and run into a problem. It is easier to do this using at least 2 brushes, one at 5 px or less to define the edges and then one or 2 larger ones to fill in the rest. However, if you change size by clicking on the brush size window at the top left, when you go back to the edit the new brush paints over the earlier application, and the "join" shows as a more intense shade (which ruins the effect).
Is this a bug or is there another way to change brush size? (I don't have this problem in Pixelmator so it is not a generic issue to using painting for colour popping).