Lets user customize the 4 sizes are available and the browser location on a screen works correctely with this extension. Why 4 sizes only? Extension's icon is nice, because it respects the Firefox UI and it consistent, if you see what I mean. But the menu design could be improved. I don't like the basic buttons that do not show anything. The hight level UI of Window Layout Resizer 0.1.3 could be a very good example to follow. I don't know witch one of this extension I will keep, because Window Layout Resizer 0.1.3 is not perfect too.