from preamble:

"Change Set: BrowserRedrawFix Date: 6 August 2003 Author: Ned Konz

Fixes the redrawing bug in the SystemBrowser (redraw didn't remove the focus rectangles).

But only invalidates the focus rectangles, so we don't have to do a full redraw.

Since we're always grabbing keyboard focus on mouseEnter, removed conditional in mouseLeave. This will prevent a PLM from responding to keyboard events once the mouse has left its bounds."!