Left arrow key during playback

In Musescore 0.9.5 and 0.9.6b2 on Windows XP: According to http://musescore.org/handbook/play-mode, the right and left arrow keys seek forwards and backwards one chord in the score while in playback mode. The right arrow key works as expected. However, the left arrow key will not progress to the previous chord, and instead repeats the currently sounding chord.