Fixed button crash when left and right buttons are clicked simultaneously.
Fixed button crash when left and right buttons are clicked simultaneously.

svn path=/trunk/libavg/; revision=3118

yyd01245/libavg,hoodie/libavg,libavg/libavg,scotty007/libavg,yyd01245/libavg,th3infinity/libavg,libavg/libavg,scotty007/libavg,th3infinity/libavg,scotty007/libavg,yyd01245/libavg,libavg/libavg,libavg/libavg,hoodie/libavg,hoodie/libavg,th3infinity/libavg,th3infinity/libavg,yyd01245/libavg,hoodie/libavg,scotty007/libavg