In the case where a join-pane is performed from within a grouped session,
and the source pane had no siblings in the window (causing the window to
be destroyed), there was an invalid access of the destination window
link (which had been destroyed as part of the group session's
resynchronization with the original session, due to killing the
now-empty source window).
CVS: ----------------------------------------------------------------------
CVS: Enter Log. Lines beginning with `CVS:' are removed automatically
CVS:
CVS: Committing in .
CVS:
CVS: Modified Files:
CVS: cmd-join-pane.c
CVS: ----------------------------------------------------------------------
