It's in JOSM and ID the same... start to draw a line and after setting the second node hit the F key and hold the F to quickly trace,   description"Follow a line or area"..
Unfortunately I cannot use the F with ID editor. In the Firefox browser as the browser intercepts the F key to launch the page search function.

To learn all the ID Editor commands hit the ? key in the editor view. There are 3 tabs in the shortcuts help view, Browsing, Editing, Tools.

cheers