Rated 4 out of 5 stars

I disagree with the people who need the actual inner viewport pixels: for that there are a dozen other good addons!

The unique thing about THIS resizer is that it measures the actual full browser windows. YES that differs from machine to machine and height of the top section is different for any person but I prefer a realworld total measurement over a theoretical "what could have been" as that is a false sense of consistency.

Back to why I retracted a star! No its not because of the added search for and hassle to install the Addon Bar. Its because when I set the browser window on my machine* to, say 1024x768, and make a printscreen photoshop measures 1014x763 and, when the browser is fullscreen it measures 2576x1616, while I have a native resolution of 2560x1600. As you see, the pixel counts are dead wrong and if this was fixed, i would give this addon seven out of seven stars and donate!

Good luck and Keep the genius vision alive by sticking to TOTAL browser measurement and not the inner window measurements since not a single person will ever use full screen for normal websurfing.

*) FireFox 54 64 bit Windows 10 64 bit.

The issue with the incorrect pixel size for a regular window is because the borders added by Windows are not included in the size, and there's no way for the extension to know how big they are. Different versions of Windows have different sizes, and you can also change the size if you want to. Windows 10 also has these borders, but Microsoft made them 100% transparent, so you don't see them but they are still part of the window size calculation. This is why the mouse cursor changes to the "resize" icon when you get close to the border of a window, even if you're not touching it yet.

Also, the fullscreen issue is the same. When Windows makes a window full screen, it really just resizes it to be a little bigger than the screen, so the borders are not visible.