Undo change beam property of first note of beamed group doesn't reset stem length

1. Create measure with a group of four beamed 8th notes.
2. Move the stem length of the last note to make the beam horizontal.

3. Select the first or second note of the group and double click 'no beam'
4. Undo

The stem length of the group is not reset. (It looks as after step 1)
This only occurs when the first note of the group is affected by the change.

Using 9f36d19 on Mac OS X 10.9.4