Consider allowing to increase the width & height after are created the square or rectangle, you can not create form first select the exact size with the mouse (the edges to become editable when you put the mouse over the edges to show an double arrow which to allow to increase or decrease the size and add checkmark who stop the edit and after to can move on the screen your created figure).
Display the unit of measurement, is it pixel, cm or inch?
To can save as predefined figure to can load in other tab/window!
Scenario: A customer tells you that the distance between the title and the photo is not exactly the same as on his competitor's website and he wants the same distance. If you can save a figure created as a predefined (by giving it a name), you can load the same figure on the other tab/window and to show him if is exactly or not, and you do not have to recreate it again.
To can generate measurable figures in units, for example: create a ruler of 24 pixels width and 4.5 pixels of height.

Sometimes its difficult to read the text on some backgrounds. When measuring, the click leaks to the page and you can end touching buttons you didnt want.

Aside from that it works great. Superb extension, thanks!


A veces es dificil leer el texto contra el fondo, y mientras estás midiendo el click de la medicion pasa de largo para el sitio así que se terminan tocando links o botones que cambian la pagina que se esta midiendo.

Fuera de eso funciona perfecto.

Working now, I think it is because I tried only on WebExtensions page.

While working on different elements, I would like to unselect all at some time. Maybe by pressing escape, right click or simple click (not dragging) can unselect the last selection.

Old:
It is not working for me in FireFox 55.0.3
I get the Icon but clicking on the icon doesn't do anything at all.
If there is a trick to use it, maybe it would be nicer if developer types a little more towards the description of the add-on like what it does and how.
Pictures aren't a bad idea.

This works fine on FF57a. Would be great if the output included the diagonal measurement in addition to width and height.