Key signature in non-pitched percussion

Musescore 0.9.5 r1770
Windows XP

A key signature appears in non-pitched percussion, such as the snare drum.
1. Create a new score with pitched instruments and non-pitched percussion.
2. Select any key signature except C major.
3. sharps or flats appear in the non-pitched percussion's key signature.

I have attached a file showing the bug.