Just realised i hadnt replied to this. I dont think its really feasable to switch out the scrolling from the drawing as this is all in haxeui-core and may also run on a non threaded env.
Im also not convinced thats the issue. As nothing much is really happening - one thing that might cause the issue is maybe the inertial scroll is causing issue. If you dont use internial scroll, is it better?
Sorry for the late reply!
Ian