The error was a memory access of a freed object. In ME_AddUndoItem I
checked the top of the undo stack to end a coalescing undo transaction,
assuming that this should be either a valid undo item, or NULL, instead
it was already freed.
The undo item being added was actually being added to the redo
Seem to be four or so new valgrind warnings in riched20 today,
probably due to Dylan's changes (though my cat may have been
sufing to friskies.com and affected the results, who knows):
http://kegel.com/wine/valgrind/logs-2008-06-27/vg-riched20_editor-diff.txt
+ Invalid read of size 4
+at ME_A
