It is inconsistent because in any other UI in Fusion 360 the CMD(mac) or CTRL(win) has to be pressed in order to add objects to the selection.
With the paint selection tool enable, however, SHIFT has to be pressed to add to the selection but then CMD/CTRL has to be pressed to remove objects from the selection. This si very counterintuitive and it would make more sense IMHO if that would be exacly the other way around.
