One useful but not so obvious tweak you can give to your Firefox installation is removing the annoyance of letting websites resize the browser's windows at their will. In spite of the somewhat sophisticated pop-up blocker that comes built in the browser, many sites still do away with popping those up and in many cases resizing either your main window or maximizing the pop-up window to get your full attention (just before you hit the X button). You won’t even need an add-on to do this.
- Go to Tools > Options
- Click on the Content tab
- Next to where it says “Enable Javascript”, click on Advanced
- Uncheck the option “Move or resize existing windows”
