Sub-beams don't work well if there's a rest inbetween

r5216.7z

Subbeams don't work well if there's a rest between
Sometimes works fine, but others not.

Fine:
1. Time signature 4/4
2. Write 2 16th notes, 1 8th silence, 2 16th notes
3. Select the 2nd, 3rd and 4th element and click "Beam 32rd sub"
4. You get what you expect to get

Wrong:
1. Time signature 4/4
2. Write 3 16th notes, 1 16th silence, 2 16th notes
3. Select the 4th, 3rd and 5th element and click "Beam 32rd sub"
4. The 3rd note has a floating half beam. That shouldn't appear

I guess it happens in every 2.0 version

Thanks!