QTextDocument::undo() will remove more than one edit block inserted by QTextCursor.

If you do the following

cursor.beginEditBlock();
cursor.inserText("A");
cursor.endEditBlock();
cursor.beginEditBlock();
cursor.inserText("B");
cursor.endEditBlock();
document->undo();

then the undo() call will remove both the A and the B, but the docs for QTextCursor::endEditBlock() indicates that it shouldn't.