Dragging handle back into its anchor makes its opposite handle move around randomly

~~We no longer can snap a handle to its anchor point, thereby hiding it (giving it a zero length status where it's treated as gone). When doing this, the other handle shouldn't be affected from its original position.~~

See the video in my comment below for what this issue is now about.

Start by watching the video linked in the issue's comment and reproducing the handle-drag behavior in the graphics editor. Trace the relevant handle and anchor interaction from the reproduced case; done means dragging one handle back into its anchor no longer causes the opposite handle to move unpredictably.

Scritto dal modello di indicizzazione a partire dal testo della issue.