Omg this an absolute LIFE SAVER. I'm currently trying to make edits to a site I'm making for someone and realized from feedback that we were seeing things differently (I have a 2560x1410 curved monitor. They have a 1920x1090 laptop. Does not compute). Tried to find an easy extension that would change my windows so I could view a window similar to how they were seeing it without having to change my display settings every time, mess with the window sizes to get that /just right/ dimension, or download unnecessary software when I only want my firefox windows to be changed.

This extension not only allows me to input my desired width and height, but also name it and create shortcut keys. Love love love.

As the creator has said multiple times in the other reviews, please make sure you understand what purpose this extension does before dismissing it as not working. Maybe it doesn't work for you because that's not the purpose it's trying to serve -- it just so happened to serve me and my idiotic thinking that everyone obviously is looking at a window in the same dimensions I am.

Edit: Cool to see it's still being updated despite last review being 2 years ago. Haven't come across any bugs yet but nice to see it's still being overseen.

Only working half-way, at best!
No matter the actual window size, if whether maximized or not, this add-on always detects and displays a window size of 632x119, and offers to use that – and only that size for a new resolution to save. Of course, the result is an unusably minute letter box size browser window without any page content visible.

I suspect the add-on's inability to detect the correct window sizes stems from the browser's protection against fingerprinting. However, other similar add-ons don't have this problem with identical Firefox settings, so this is a no-go for me with this WindowSizer add-on.

The setting of the window size itself might work, though. I didn't really take the time to measure whether the resulting window really had the 632x119 pixels. ;)

Heart-broken and disappointed, Dr. Cheap ... Had high hopes ... Wanted to give ONE MILLION STARS, but I can't set the font size ... [edited -- no, more, the magnification / resolution of the page ... or, would it be scaled scaling, not sure]. I so hoped that I could set a Profile on this where I can read my Google Mail in the 120% size of a window at 1920 x 1080. But, there is no place here to select font size. If that would have been here, I'd have let my wife carry your babies ... {Grin} ... But, please, add that feature and I'll give you 100,000 reviews. Maybe, even add URL to that list where you can have a checkbox that will auto-change window when visiting that URL. That's an idea too.

Please, please, please ... keep improving this extension. It has great potential. But, right now, is useless for me, and I don't see the purpose really of it now in current state ...

Okay, I found this extension, "Zoom Page WE", and I think that is more what I needed. Maybe, I didn't understand clear purpose of this extension. Because I need that ZPWE. Okay, I'm going to raise my rating from 2-stars to 3-stars. But, still, please, consider the suggestions that I made.