Rob--W
commented
3 years ago Did this start happening in Firefox 86? This is probably due to dynamic First-Party Isolation, aka "Total Cookie protection" (https://blog.mozilla.org/security/2021/02/23/total-cookie-protection/) (https://bugzilla.mozilla.org/show_bug.cgi?id=1686296). This feature is enabled when you've enabled Enhanced Tracking Protection (cross-site cookies), i.e. having the network.cookie.cookieBehavior preference set to 5.
My Cookie Manager extensions is unable to delete cookies because extensions are unaware of this feature. Support for this feature is being tracked at https://bugzilla.mozilla.org/show_bug.cgi?id=1669716 . I'm the assignee to this bug (as a Firefox engineer), so I should be fixing this issue in any case...
ericmberg
I have been using Cookie Manager since Jan. 2020 with great success. (Environment: Dell Inspiron 15-7567 laptop running the latest version of 64-bit Windows 10 Professional and the latest version of 64-bit Firefox -- currently 88.0. I'm attaching a screenshot showing the browser extension that are installed.)
However, starting a couple of months ago, Cookie Manager was no longer deleting all the cookies that I was trying to delete manually. For example, if I wanted to delete all the cookies in a container, I would set the "Cookie Jar" field to one of my Firefox containers, click Search, click Select All, then click Delete Selected. (If any of the cookies happen to be whitelisted, I get a prompt to unlock them, and I run Delete Selected again on the unlocked whitelisted cookies.) All the cookies that are visible are now dimmed out to show that they are deleted.
At this point, when I click Search again, many of the cookies have been removed, but some still remain. I haven't noticed any patterns in which cookies remain (e.g. it's not that they were all whitelisted cookies that I had unlocked.) And, for the cookies that remain, if I try deleting them one by one, each one dims out, but then reappears after I click search. Also, for the cookies that remain, if I use the Edit button and try to make some changes in the data fields and then click Save, the original cookie is still there in its unmodified state, and it has created a new duplicate of that cookie that does include my edits.
This doesn't only happen if I click Select All. Even if I select cookies individually, or do a multi-select (click on one cookie and then drag the mouse pointed down to select adjacent cookies), I get the exact same problem.
Unlike one of the earlier bug reports, where Cookie Manager displays an error message for tabs that it can't delete, in my case, it just fails silently (no error message).
The only thing about my use of Firefox that might be unusual is that I have 4 Firefox windows open and a lot of tabs in each window -- in one of the windows, I have hundreds of tabs. When I exit Firefox, I do so by killing its process using Task Manager. Then, when I restart Firefox, all the tabs reappear but are blank -- the contents of a tab don't get loaded from the website until I click on it. (That's how I can have hundreds of tabs open without having performance get very bad.)
Some of the cookies that I'm trying to delete are associated with pages that I currently have loaded. I don't know whether that's causing the problem. However, I was using Cookie Manager in the same way (hundreds of tabs open and trying to delete cookies associated with loaded pages) during all of 2020 and at the start of 2021, and Cookie Manager didn't have any problems.