adds missing scroll event in drawer; resolves #281
adds missing scroll event in drawer; resolves #281

agamemnus/wavesurfer.js,agamemnus/wavesurfer.js,ale-grosselle/wavesurfer.js,katspaugh/wavesurfer.js,ffxsam/wavesurfer.js,katspaugh/wavesurfer.js,ale-grosselle/wavesurfer.js,ffxsam/wavesurfer.js