Horizontal movement of an note causes accidental to disappear

Moving a note *horizontally*, which I did by accident (sic), causes the accident associated to that note (if any) to disappear. There is no way to have it come back, I try to put a natural on it, then a sharp (or flat), or move it vertically, but the only workaround is to delete the note (converting it to a rest of the same value) then re-enter it.

MuseScore 0.9.6.3 (latest official release) on Windows XP Professional SP3.

Ciao
Fabrizio