xterm multi-windows freeze

[Lester Ingber]

At least once a day, for the past week or so, my xterms freeze
("not responding").  I can kill the processes under my master console
that brings up XWin, so I'm pretty sure this is an XFree problem with
XWin -unixkill -emulate3buttons -clipboard -multiwindow &

My XWin.log file ends with:
winTopLevelWindowProc - BitBlt failed: The handle is invalid.

OsVendorReset - Hello
winClipboardProc - Call to select () failed: -1.  Bailing.
OsVendorReset - Clipboard thread has exited.
winInitMultiWindowWM - Caught IO Erro.  Exiting.
winDeinitMultiWindowWM - Noting shutdown in progress

stdout (piped to another log file) reads
winMutliWindowWMIOErrorHandler!

Lester