Disallowed actions included in undo of tremolo

1. Open attached score (produced in 1.1).
2. Select first note.
3. In Palette, double-click a '1/16 through stem' five times.
4. Undo.

Expected result: The previous state (1/8 through stem) appears.
Actual result: You have to click a further four times before the previous state (1/8 through stem) appears.

Using MuseScore 2.0 Nightly Build (5290) - Mac 10.6.8.