GS/OS System 6.0.1 Not Repainting Windows

[isbat1@yahoo.com (Anonymous Coward)]

As the subject indicates, I'm having trouble with my install of GS/OS
6.0.1.  I've got a 1 GB hard drive, with three 32 MB ProDOS
partitions, and the rest as an HFS partition.  System is ROM 03, with
ZipGS, RamFAST Rev D 3.01E, and 4 MB Sirius Ram card.

The problem is, occasionally GS/OS does not properly repaint windows. 
I see this a lot with Finder, and also under Orca/C 2.0.1.  In the
compiler, it's the source code (text) window that fails to repaint. 
In the Finder, it's the contents of a window when browsing my HFS
partition.  The Finder windows will repaint their content if I do a
"select all"; I can see what I've selected in a window that was
previously empty.  This doesn't happen all the time, though, not even
on one partition versus another.  I can identify no pattern to this
behavior.  I cannot reproduce it on demand.

What might be the cause of this failure to repaint?  Is this a known
issue?  What steps can I take to resolve this?