This does not seem to work in V2013 pro. I was able to activate the toolbar and even interact with it, as well as enter a value but no line appears when a position for one is clicked on a model. Thought you would like to know.
Take care.

I would be interested as well, simply because I am not so sure that it does such a thing.

Sounds like some of the users in this post need to move to another software. This is called Sketch-Up for a reason. I was most likely developed by someone that was tired of the limitations of pencil and paper. It is meant for sketching out ideas quickly without the fuss of all that you people bring to it. I despise the other programs because of their complexity. I use them (Rhino and Modo) of course because they are unnecessary but not at the beginning of a project that has no initial parameters. Do not try to make it so hard on yourselves, it steals all the fun out of it.
BTW, has anyone tried View>Toolbar>Save Toolbar Location/Restore Toolbar Location. I crash (Bug-Splat) Sketch-Up all the time and I have yet to manually move all my toolbars back to their positions after restoring them.