Most of the mask modes do not overlap

[davidh]

Use a shape to create a mask -> Apply it
Choose the overlap mode
Draw any other shape partly over it and Apply it-> except Oval no one overlaps it

If you create a mask using left, right or bottom half options and then overlap it with any shape except Oval the mask gets clipped in its bottom part.

The "half mask" options are useful. I wonder if anyone finds it useful, if they work as they do only with Add mode and with other modes correspondingly to each mode. This way you could mask any single quater of the image very fast. And with Invert the diagonaly placed quarters. Just an idea :).

[jsachs]

Fixed for next release.