Is there a way to keep the Firefox rulers that show up when you hover over an element in inspect element? If you don't know what rulers I'm talking about, it's the following, from this post. I need the rulers to stay visible, to help with aligning content.
EDIT
There's a button next to most rules that allows you to select them "permanently". It's almost what I want, except it doesn't show the rulers. Here's the button (the white cross-hairs box)
It might be possible to get that button to also show rulers? Currently it just shows the box model (for 'Cats' and 'Dogs' in the picture):
