Followup resize transformation: potential performance regression

potential performance regression with complex outlines

Just:
I think we may have a bit of a performance problem with (very) complex outlines, as the relatively expensive getSelectionBounds() call is performed at every mouse move. I’m not yet sure what to do about it, maybe we need to followup with some optimizations. While the outline is not changing and while the selection is not changing, the getSelectionBounds() call will always return the same.