Dec 20, 2009
I'm not sure when it happened, since I don't use it all that frequently, but firefox/iceweasel changed the default behaviour of Ctrl+Scrollwheel from Zoom in/out to moving back and forth in history. If you want to change it back to controlling the zoom of the page, you can open about:config and change mousewheel.horizscroll.withcontrolkey from its default value of 0 to a value of 3. There are other values you can set that have other functions.. If you're interested, I found the info at http://kb.mozillazine.org/Firefox_:_FAQs_:_About:config_Entries.