How do I do gtk mouse interaction correctly with Haskell Chart library? -

i'm using this library

as of have point follows mouse, kind of works because assume window 500x500, , point never directly behind mouse because (0,0) on graph not (0,0) on window.

if figure out graph origin relative window's coordinates, fix everything, can't seem figure out how that. graphics.rendering.chart.renderable seems relevant, such "pick function" , rectsize, again i'm not sure how relevant it. graphics.rendering.chart.backend may relevant.

or may solve gtk? don't know.

please help, has been killing me.

edit: here's current code if helps