Using Firefox 20.x , configured to always be in private browsing mode. For some reason, after a while of browsing, when I open a new empty tab, there is content saved on the dashboard of recently visited sites. This seems almost exclusively to happen only with images from i.imgur.com . These sites do not go away after closing and reopening the browser. The only way to get rid of these is to clear all my recent history. I should not have to do this, as my browser is always in privacy mode.
I am really not sure how to test this. If I clear my history, and go to imgur links, it does not happen right away. After a few days of web surfing, I will open a new blank tab and see there is content available in the new tab window. All those spaces should be empty.
Any ideas on how I can hone in on what is going on here?
You can remove all data stored in Firefox from a specific domain via "Forget About This Site" in the right-click context menu of an history entry ("History > Show All History" or "View > Sidebar > History") or via the aboutermissions page.
Using "Forget About This Site" will remove all data stored in Firefox from that domain like bookmarks, cookies, passwords, cache, history, and exceptions, so be cautious and if you have a password or other data from that domain that you do not want to lose then make a note of those passwords and bookmarks.
You can't recover from this 'forget' unless you have a backup of the affected files.
It doesn't have any lasting effect, so if you revisit such a 'forgotten' website then data from that website will be saved once again.
Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance).
Do NOT click the Reset button on the Safe Mode start window or otherwise make changes.
The issue came back even with Firefox 21. Its been working fine since the upgrade last week. But just now I initiated a new tab, and there are 3 imgur links remembered in my dashboard (or whatever you call that screen). What's very strange is that this only ever seems to apply to imgur links, no other sites ever seem to be remembered.
Well, it looks like this was related to the Reddit Enhancement Suite (RES). I was finally able to replicate the issue. I noticed that this would only happen to Reddit links I would click when using the "View Images" feature of RES inside my Reddit user profile. Once you did this, and subsequently clicked on an imgur image from your reddit profile, it would stick in Firefox's memory even with privacy mode turned on.
I updated the RES plugin, and now the issue seems to have gone away. Maybe this was a bugfix on their end or something.