Off-canvas node pin

Hi,

I have noticed that when I click on a node and drag it off-canvas, that node gets pinned outside of the canvas region. I think the drag event is lost when the cursor goes outside the canvas.

Start by reproducing the issue in the canvas interaction code: select a node, drag it beyond the canvas, and observe whether the drag event is lost. Trace how node dragging and pointer events are handled at the canvas boundary. Done means dragging outside the canvas no longer leaves the node pinned off-canvas.

Written by the indexing model from the issue text.