Make Google Chrome "forget" zoom level once a tab is closed

Upon further discovery, this was reported back in May as having been present in Incognito mode, too. My testing using Chrome 7.0.517.44 shows that it does not happen in Incognito, although I did a purge within Incognito, too. In any event, in REGULAR mode, Chrome stores your domains and zoom levels in the Preferences file (found, on Win 7 Pro 64 bit, at c:/Users/NAME/AppData/Local/Google/Chrome/User Data/Default) whether you purge your history or not. You can open this with Notepad and manually edit out the listings. Was interesting to see everything that was listed in there, including ancient browsing history. This file also includes some entries for "most visited blacklist" but these are hash files, and not overtly-listed domain names like the zoom level listings. This is definitely a bug in Chrome, as purging your history does not remove these entries from Preferences. This, then, begs the question of what other files maintain URL info in them, too. For now, the only solution is to use Incognito, or remember to never zoom in Chrome regular mode.

I know this is a really old question, but I was googling for a way to do the same and found an extension called Per Tab Zoom that can make CTRL+Scroll Wheel to zoom tabs independently of each other.

When you close a tab, its zoom setting is forgotten.
You can customize a few shortcuts to perform the kind of zoom you want. "Per tab" zoom is forgotten when the tab is closed and "per domain" zoom is remembered for all pages in that domain.

This is a real problem because it shows that Chrome still retains browsing data even after purging the history and all previous stuff. Despite a purge, your zoom level is retained for the domain, which means somewhere in the guts of Chrome is a listing of all domains and their zoom levels, which never gets purged. I have not tested this in Incognito mode. Google needs to fix this, or really reveal what gets retained in its browser after a purge.