Changes to instrument group produces wrong bracket span

1. Open attached score (produced in 1.3?).
2. 'Add'>'Instruments…'.

Step set 1

3. Click on each electric guitar stave and 'Add Stave'.
4. 'OK'.

Result: Bracket for electronic organ is removed.

5. Apply bracket to the electronic organ.

Result: The bracket sticks out.

Step set 2

3. Remove either piano.
4. 'OK'.

Result: The bracket for electric bass is removed.

5. Apply bracket to electric bass.

Result: The bracket sticks out.

Using MuseScore 2.0 Nightly Build (b6480b7) - Mac 10.7.5.