in handdrawing widget, only bind mousemove and mouseup/mouseleave after mousedown is triggered
in handdrawing widget, only bind mousemove and mouseup/mouseleave after mousedown is triggered

bloomberg/bqplot,dmadeka/bqplot,rmenegaux/bqplot,bloomberg/bqplot,ChakriCherukuri/bqplot,ChakriCherukuri/bqplot,SylvainCorlay/bqplot,ssunkara1/bqplot,SylvainCorlay/bqplot,SylvainCorlay/bqplot,ChakriCherukuri/bqplot,rmenegaux/bqplot,bloomberg/bqplot,ssunkara1/bqplot,dmadeka/bqplot