How to draw line on the canvas in layout vertical scroll arrangement

when dragged on canvas included in layout vertical scroll arrangement, i want to draw line.
But, that is impossible because screen scrolling might have higher preference than dragged event on canvas. how to solve it?

Maybe this extension can help ?

Scroll Arrangement Handler

thank you very much!!
but, it can’t solve my problem!!

You are right, i had hoped that the “User Control” block would help, but it doesn’t.

Can’t find a way at the moment, does the canvas have to be in a scrolling arrangement?