Ever been manually entering a URL into Firefox and then switched windows only to come back to Firefox and have the entire URL contents highlighted? If you don't notice and resume typing, the entire contents of the URL bar are accidentally deleted. If you regularly type out or edit URLs this gets really annoying—fast! The Pain in the Tech weblog explains how you can edit Firefox's settings in about:config to change this behavior. All you need to do is find browser.urlbar.clickSelectsAll in about:config and change the value from true to false. Kiss those accidental deletions goodbye. On the extension side, Uppity makes a great companion for users that manually edit loads of URLs.
Firefox address bar tweaks [Pain in the Tech]