Just click Dr.Body Narrow toolbar icon and current page will change it's width, making it comfortable to read toooooo-wide-texts.
In new versions you are able to choose one of 600, 760, 960, 1240, 1560, 1880 pixels on your choice, which one is more comfortable for you.
Also the Dr.Body Narrow add-on allows you to stick page to the left or right side of the window, or center it - as you like.
Extension doesn't put itself on toolbar by default, so you have to drag it's button to toolbar via "Customize...".
· Mozilla Firefox
What's New in This Release: [ read full changelog ]
· Added "Force" mode, that allows agressively reduce page width (removes fixed element's sizes, so page can shrink freely).
· May be useful if page doesn't want to shrink.