Sticky ruler lines in firefox developer edition

Question

I've started using Firefox developer edition, after many years of using Firefox with firebug. A slightly annoying artifact that I cant seem to get rid of are the rule lines - when I select an element (e.g. a button) Firefox developer edition adds rulers to the page (dashed blue lines) and highlights the elements in yellow.

The issue I'm having is that these rules (sometimes) appear fixed on the page - they don't move with the selected elements and I cant make these rules and highlights disappear (alternatively, I can't make them stick by myself), I've tried every setting in the console, I've tried refreshing the page, all to no avail, the only way I can seem to get rid of them is to navigate to another page and back to my original page.

Does anyone know a setting, or a keyboard shortcut to make these lines go away? is it a bug in Firefox?

Answer 1

To answer my own question:

It seems the only way to get rid of the rulers without navigating to another page is to close the inspector, and re-open again (a quick double-press of F12 does it) - others don't have the same issue with the same version of Firefox developer edition, Though I cant find a bug-report about this