Works great! Exactly the functionality missing from other Add-ons.

Great, Gives exact size of each html element used

Works as expect but font size is very small, would be good to have an option to increase it.

It took just a little time to get used to this tool. Now, it's really convenient to measure everything, at least what I needed to measure!

Can't select inside iframes. Apart from that, this extension is priceless. It's incredibly helpful and I use it almost anytime I have to do a requirement about a graphical interface.

Did work as expected. The only thing I would recommend is to exit extension mode by using ESC key.

Almost ideal, it would be nice to have option to enable smooth animations(like `transition: 0.2s all`) in addon

Thanks! Exactly what I need. I use Smart Page Ruler on Chrome but couldn't find anything similar on Firefox until now.

It has been top notch, but lately has been a little bit buggy. After using it, the browser just get buggy, the buttons in a page stop working, if you click the add-on again it doesn't work anymore. I need to refresh the page to make it work again

Exactly what a web dev needs!!!