Unless you are using extensions or scripts to change things firefox will normally remember zoom on a per site basis. So if you look at his forum on 100% and a wiki at 240% next time you open them that is what you see. All you need to do is set the wiki to the magnification you need whilst you are using it and then close it, next time that is what it should display as.

• see how do I use zoom

Thanks for the response John99. I always reset to 100% magnification, but successive Wikipedia accesses still retain 240% magnification. This problem has only appeared recently with my download of Version 10.0.1. Reboot or clearing out cookies and temporary files also doesn't make any difference.

Hi John 99, Success. If I reset the magnification from the View tab on the Menu toolbar, the magnification stays set - which was your point. However if I reset using the Zoom facilities on the Add-On bar, the change isn't remembered. Investigating further, I see I have the Add-On's "Page Zoom Buttons 1.1.5" and "Zoom Page 3.0" installed - which I hadn't appreciated, so I guess results are bound to be unpredictable. I will get rid of one and experiment - "egg on face" possibly!

Glad its working. Thanks for posting back.

All problems are difficult or unexplained until the answer is found! Hopefully these solved threads help others with similar problems.