I've noticed a bug in LiveWriter.
If you cut and paste some text, then press undo/Ctrl-Z, it seems to forget the most recent step (i.e. the paste), and undoes the steps previous to that.
i.e.
This is a test. this is also a test.
Now cut "This is a test" and paste it on the end and then press undo and you end up with!
This is a test. this is also a test.This is a test.