I've had a problem for a while, basically whenever I pull up the main map (hit 'M') and right click to zoom out it zooms right back in. Sometime it gives me a few seconds to click on another zone, but then it will just zoom back in to the zone I'm in. Make setting way points annoying at best, makes trying to find where the scourge is invading maddening.
As I said, this problem started a while ago and mostly I've just lived with it, figuring I'd get around to tracking it down sometime. When it started I was using Cartographer, I ended up switching to Mapster because I originally thought it was Cart that was causing it. I've also gone from Chinchilla to Squeenix and back, made no difference. Everything map related, and most of my other mods, have changed since this started, thanks to 3.0, and still it continues to plague me. It's worse in some areas -- Ata'mal Terrace, for instance, is horrible, but things get better if I fly off a little ways -- and seems to be related to something happening around me, but I'm not sure exactly what.
Oh, and I've changed video cards (ATI9550 to ATI3650), albeit not because of this, and added memory, and still it persists.
If anyone has any suggestions as to what might be causing this or where it would be best to start looking next, I'd be very appreciative.
I briefly had this problem many months ago; it turned out to be a bug in the Wowhead Looter data gathering addon. It's long since been fixed, but other mods might be doing the same thing.
If you search through your Interface folder for files containing the strings SetMapToCurrentZone or SetMapZoom, you'll see which addons could be doing this behavior. Then you can try disabling them all and enabling them individually to narrow down the culprit. At that point some code inspection would be needed.