Applying double-note tremolo to dotted notes fails and alter measure duration

MuseScore 0.9.6.2

- Create two dotted quarters
- Drag and drop a tremolo symbol on the first one.

Expected result : Two dotted half notes with a tremolo
Actual result : Two half notes without dot.

If you undo (Ctrl+Z), then you have 2 quarters and a quarter rest.

First reported by lossfabulous