problem

shows the effect of moving a point. The user positions the mouse cursor near some polyline
vertex, presses down the mouse button, and “drags” the chosen point to some other location before releasing
the mouse button. Upon release, the previous lines connected to this point are erased, and new lines are drawn

[UrbanLegend]

And what are you asking for here ?

Sorry i don't see your question only an outline of some problem