Hi again.
I have noticed that if I am painting in 3D mode, or in 2.5D, that if I paint an area and then zoom back out (and if I was in 2.5, getting out of 2.5 mode, first), that there has been random painting somewhere else in the model. At first I thought it was something happening in 2.5D mode, where maybe the painting was projecting through the entire model to the other side as well as the front, but this happens in 3D mode too. And it is clearly not a projecting-through issue…It will paint somewhere else entirely. Very annoying to have to go back and fix these types of problems especially if they were high detail areas.
Update: This also happens when I hide areas with the red rectangle (Shift-Cntrl-Alt Drag LMB). Areas that are not even on the screen, somewhere entirely else on the model also get hidden.
At any rate, I think I am doing something fundamentally wrong here.