I do not understand how this can be a recommended add-on. Yes, it does the job and it looks pretty and all that. But I have never had an add-on that made my pages freeze up and cause my browser to crash before this. It's almost impressive to see how they managed to mess up such a simple thing. Refreshing pages take forever and when I resize my windows all of my tabs lock up, stuck between the original width, to the new width and everything in-between. How do you manage to make something that is supposed to only change the appearance but somehow invents more problems??