In order to keep cookies only until I close Firefox, I have to turn off (uncheckmark) Always Use Private Browsing Mode. This is exactly counterintuitive. Either add an explanation next to Edit menu > Preferences > Privacy > History > Always Use Private Browsing Mode or, better, include deletion of all cookies at each session's end as part of private browsing mode. This is in FF 40.0 for openSuse 13.2 Linux. Related is bug 1151356.

This WFM on Firefox 41 beta on OS X (I don't have 40 around to see if it's broken for me there). Can you test a beta version to see if this is fixed? ( https://beta.mozilla.org/ ) If it's still broken there, can you try creating an additional new (clean) Firefox profile ( https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles ) to see if you can reproduce it there? (FWIW, I tested with https://wiki.mozilla.org/ , and I was logged out after closing and restarting Firefox - it might be useful to provide more details about what cookies you see persisting when using permanent private browsing mode)

A test produced unreported cookies. Repeatedly, FF said there were no cookies, but when I turned private browsing off cookies were reported, apparently old ones that are session cookies that didn't get deleted even after FF was closed and the computer was warm-rebooted. This was the test, run on FF 40 (not beta): No settings changed from past practice: -- Edit menu > Preferences > Privacy: -- Tell Sites That I Do Not Want to be Tracked: cleared (uncheckmarked) -- Firefox Will: Use Custom Settings For History -- Always Use Private Browsing Mode: cleared -- Accept Cookies From Sites: checked (checkmarked) -- Accept Third-Party Cookies: Always, with no Exceptions -- Keep Until: I Close Firefox -- Clear History When Firefox Closes: checked -- Clear History When Firefox Closes: Settings: When I Quit Firefox, It Should Automatically Clear All: History: Cookies: checked Iteration #1: same settings except: -- Always Use Private Browsing Mode: checked - visited (without logins, clicks, or entries) google.com, amazon.com, youtube.com, & yahoo.com, producing (surprisingly) no cookies - visited (without logins): --- google.com & searched for Mars (no ads on 1st search results page) then baseball (no ads on 1st search results page) then clothes (no ads on 1st search results page) then John Smith (no ads on 1st search results page) then toy telescope (including ads) then Chevrolet (including ads) --- amazon.com & clicked on 3 products on home page then searched for dictionary --- youtube.com & clicked on 1 video then watched 2 & a fraction videos in automatic sequence --- yahoo.com & clicked on 2-3 items the latter 2 being ads hosted by supertechconsult.com & motifinvesting.com each opened in separate tab, producing (still surprisingly) no cookies Iteration #2 (after closing Firefox & gedit & installing newly-announced OS update (which may have included FF to version 40.0.3, a number I don't remember from past) including reboots then visiting npr.org & clicking 3 links): same settings except: -- Always Use Private Browsing Mode: cleared - cookies found (45 total) (domains only): adnxs.com, disqus.com, doubleclick.net, google.com, imrworldwide.com, liverail.com, npr.org (14 cookies), openx.net, pixel.rubiconproject.com, pubmatic.com, rfihub.com, rubiconproject.com, & scorecardresearch.com - cookie duration: every cookie labelled "Expires: At end of session" Iteration #3 (after Remove All cookies, closed browser (alt-F4), & visited npr.org with clicks on same links as before): same settings: - cookies found (domains & counts): same as before plus demdex.net (1 cookie), ford.demdex.net (2 cookies), & youtube.com (2 cookies) - cookie durations (additional domains only): every cookie labelled "Expires: At end of session" After that, I applied Remove All cookies, quit using File > Quit, restarted FF, and found no cookies. So, manual deletion through FF worked. But that's not enough, because the settings promised to do it automatically and they didn't. If cold boot makes a difference vs. warm reboot, it shouldn't, because if cold provides better cookie deletion then warm reboot should, too. Logging into websites I visit might make a difference about adding or deleting cookies, maybe different cookies. For an FF-beta test, I'd rather not install and run the beta. Time is an issue and being left with a beta version means rolling back for productivity work, on which I'm behind, and rolling back might be tricky. I'm hesitant to depart from what the distro is using, lest dependencies be a problem. But maybe someone else can manage the risks and the time better than I can. Related is bug 1201353.

(In reply to Nick Levinson from comment #2) > Iteration #2 (after closing Firefox & gedit & installing newly-announced OS > update (which may have included FF to version 40.0.3, a number I don't > remember from past) including reboots then visiting npr.org & clicking 3 > links): same settings except: > -- Always Use Private Browsing Mode: cleared > - cookies found (45 total) (domains only): adnxs.com, disqus.com, > doubleclick.net, google.com, imrworldwide.com, liverail.com, npr.org (14 > cookies), openx.net, pixel.rubiconproject.com, pubmatic.com, rfihub.com, > rubiconproject.com, & scorecardresearch.com > - cookie duration: every cookie labelled "Expires: At end of session" ... and the cookies were gone after you exited, or not? :-) > > Iteration #3 (after Remove All cookies, closed browser (alt-F4), & visited > npr.org with clicks on same links as before): same settings: > - cookies found (domains & counts): same as before plus demdex.net (1 > cookie), ford.demdex.net (2 cookies), & youtube.com (2 cookies) > - cookie durations (additional domains only): every cookie labelled > "Expires: At end of session" And after a restart of Firefox, before visiting any sites (and presumably without your homepage set to somewhere that sets cookies), the cookies were still there? It's unclear to me whether you restarted before checking for cookies, or not, given that you then said: > After that, I applied Remove All cookies, quit using File > Quit, restarted > FF, and found no cookies. The point of the "clear history when Firefox closes" is that the cookies should get removed when Firefox closes, but not before... > So, manual deletion through FF worked. But that's > not enough, because the settings promised to do it automatically and they > didn't. > > If cold boot makes a difference vs. warm reboot, it shouldn't, because if > cold provides better cookie deletion then warm reboot should, too. Sure, there shouldn't be a difference there. In fact, rebooting the machine shouldn't be related at all. I tried to reproduce the NPR thing on 40.0.3 on Windows. I saw a similar set of cookies before restarting Firefox. Then I closed all the NPR tabs, closed Firefox, reopened Firefox on the same profile, and the list of cookies in the options came up empty. At this point I'm not sure what's causing the cookies to not be deleted on your machine after a Firefox restart. :-\

I have had the browser set all along so that when FF starts it's to show a blank page. That shouldn't be writing any cookies; if it does, something should tell us. It appears that FF is telling us that cookies are deleted or going to be deleted when they're only being hidden and a change of settings makes them visible again. Iteration #1 ended with no cookies but iteration #2 had 31 cookies not explicitly from npr.org. In iteration #3, after I applied Remove All cookies, emptying the list of cookies, I visited only npr.org and nonetheless there were 36 cookies other than explicitly from npr.org. I ran a new test on FF, this time in root: I set FF to open to a blank page. I removed all cookies, assuming there were any. I went to this Mozilla bug page that you're looking at now. This produced cookies from bugzilla.mozilla.org (2 session cookies) and login.persona.org (1 session cookie & 1 cookie persistent till next month). In Edit > Preferences > Privacy > History > Remove Individual Cookies > Cookies, I applied Remove All. I renamed the cookies file (automatically causing a copy of it, so that the unrenamed cookies file would still operate normally) by appending ".txt" but trying to open it in gedit repeatedly caused the session to freeze and I had to log in again. I visited google.com, amazon.com, yahoo.com, & youtube.com and got cookies; in Edit > Preferences > Privacy > Remove Individual Cookies > Cookies, I removed every persistent cookie (there were at least a dozen) & thus kept 4 session cookies. In the same Privacy settings, I changed Remember History to Never Remember History. After FF restarted, I applied control-q, quitting. I again restarted FF, which automatically opened tabs for Preferences & Mozilla, but not YouTube. In the Privacy settings, I changed Never Remember History to Remember History, causing a restart. The Cookies dialog now listed 2 cookies from youtube.com, both persistent. That means the 2 cookies survived removal of all persistent cookies, a new resetting to never remember history, & quitting FF.

(In reply to Nick Levinson from comment #4) > I have had the browser set all along so that when FF starts it's to show a > blank page. That shouldn't be writing any cookies; if it does, something > should tell us. > > It appears that FF is telling us that cookies are deleted or going to be > deleted when they're only being hidden and a change of settings makes them > visible again. Iteration #1 ended with no cookies but iteration #2 had 31 > cookies not explicitly from npr.org. In iteration #3, after I applied Remove > All cookies, emptying the list of cookies, I visited only npr.org and > nonetheless there were 36 cookies other than explicitly from npr.org. npr.org makes HTTP requests to numerous other domains that set those cookies (on their domains), so the behaviour you describe is expected. Nothing to do with Firefox "hiding" cookies or anything like that. > I ran a new test on FF, this time in root: I set FF to open to a blank page. > I removed all cookies, assuming there were any. I went to this Mozilla bug > page that you're looking at now. This produced cookies from > bugzilla.mozilla.org (2 session cookies) and login.persona.org (1 session > cookie & 1 cookie persistent till next month). In Edit > Preferences > > Privacy > History > Remove Individual Cookies > Cookies, I applied Remove > All. I renamed the cookies file (automatically causing a copy of it, so that > the unrenamed cookies file would still operate normally) by appending ".txt" > but trying to open it in gedit repeatedly caused the session to freeze and I > had to log in again. I visited google.com, amazon.com, yahoo.com, & > youtube.com and got cookies; in Edit > Preferences > Privacy > Remove > Individual Cookies > Cookies, I removed every persistent cookie (there were > at least a dozen) & thus kept 4 session cookies. In the same Privacy > settings, I changed Remember History to Never Remember History. After FF > restarted, I applied control-q, quitting. I again restarted FF, which > automatically opened tabs for Preferences & Mozilla , but not YouTube. I tried to reproduce your steps, but I got lost here. You set the homepage to "open a blank page", and quit Firefox, after you'd set "never remember history". Then you re-open Firefox. At this point I get only 1 (blank) tab - which makes sense, because no tabs got saved and there's no history. Where did the tabs for preferences & this bug come from?

Before responding: Bug 781983 may be relevant. In response to the last post above: I think I must have erred in my description (I don't know why I would have slipped). I just tried the particular step that stopped you and also got a blank page. (Maybe I added the two pages manually, stepped away, and forgot I had manually done so.) That's my fault with the description. However, that error doesn't seem to make a difference for the problem being reported. I'll explain below. This is a rewrite of the above, with steps separated, in case this is easier to follow: I went to my Linux root account and started FF. I set FF to open to a blank page. I didn't check if there were any cookies but, in case any were present, I selected to remove all of them. I went to https://bugzilla.mozilla.org/show_bug.cgi?id=1201354 (i.e., this page that you're looking at now). I checked what cookies FF had at this point. There were four, of which three were session cookies and one was persistent, set to expire next month. I went to Edit > Preferences > Privacy > History > Remove Individual Cookies > Cookies. I applied Remove All. This step is tangential and can be skipped while doing the rest of the test: I renamed the cookies file. Renaming automatically caused a copy of it to be made, so that the unrenamed cookies file would still operate normally. The renaming was by appending ".txt" to the filename. However, trying to open the *.txt file in gedit repeatedly caused the session to freeze and I had to log in again. This ended the tangential step and the main procedure can be resumed with the next step. I visited google.com, amazon.com, yahoo.com, & youtube.com. Cookies appeared. In Edit > Preferences > Privacy > Remove Individual Cookies > Cookies, I removed every persistent cookie (there were at least a dozen) & thus kept 4 session cookies. I kept no persistent cookies at this point. Only session cookies were kept. In the same Privacy settings, I changed Remember History to Never Remember History. This change automatically caused FF to restart. A dialog announced this and let me cancel the setting change, but I wanted the setting changed, so FF restarted. After FF restarted, I applied control-q, thereby quitting. I again restarted FF. In the Privacy settings, I changed Never Remember History to Remember History, causing another restart. I looked at the Cookies dialog, which at this point listed 2 cookies from youtube.com, both persistent. That means the 2 cookies survived removal of all persistent cookies, a new resetting to never remember history, & quitting FF. When I reran parts of this test due to my apparent error acknowledged above, while the preference was set to Never Remember History, I opened yahoo.com, google.com, amazon.com, & youtube.com. After each of the four home pages had loaded, I closed each of the 4 tabs. Because Never Remember History was in effect while those home pages fully loaded and while I closed the tabs, FF should not have remembered their history. Then I changed the preference to Remember History, causing a new restart. I opened no new tabs, looking only at Preferences. This time, I found 3 cookies, all from Amazon, all to be persistent for more than 2 decades. This means that while Never Remember History was in effect, history was being remembered by FF, and the fact of FF remembering history was not visible until I elected for FF to Remember History.

(In reply to Nick Levinson from comment #6) > Before responding: Bug 781983 may be relevant. No, that's related to indexeddb/localstorage, not cookies. > I went to my Linux root account and started FF. I set FF to open to a blank > page. I didn't check if there were any cookies but, in case any were > present, I selected to remove all of them. Note that running Firefox from root is unsupported and has issues. I ran Firefox from a normal user profile. > I went to https://bugzilla.mozilla.org/show_bug.cgi?id=1201354 (i.e., this > page that you're looking at now). > > I checked what cookies FF had at this point. There were four, of which three > were session cookies and one was persistent, set to expire next month. > > I went to Edit > Preferences > Privacy > History > Remove Individual Cookies > > Cookies. I applied Remove All. > > This step is tangential and can be skipped while doing the rest of the test: > I renamed the cookies file. Renaming automatically caused a copy of it to be > made, so that the unrenamed cookies file would still operate normally. The > renaming was by appending ".txt" to the filename. However, trying to open > the *.txt file in gedit repeatedly caused the session to freeze and I had to > log in again. This ended the tangential step and the main procedure can be > resumed with the next step. So, I never did this because I didn't understand what the point of this step was, nor how "renaming automatically caused a copy of it to be made" - automatically by who? - it's quite likely to mess with things though. Can you reproduce without doing this? Your labeling this as tangential suggests that, but you repeated it here so I'd like to be sure. > I visited google.com, amazon.com, yahoo.com, & youtube.com. And then closed the tabs, right? > I looked at the Cookies dialog, which at this point listed 2 cookies from > youtube.com, both persistent. That means the 2 cookies survived removal of > all persistent cookies, a new resetting to never remember history, & > quitting FF. I couldn't reproduce this on either OSX or my Linux VM (Ubuntu 14.04). > When I reran parts of this test due to my apparent error acknowledged above, > while the preference was set to Never Remember History, I opened yahoo.com, > google.com, amazon.com, & youtube.com. After each of the four home pages had > loaded, I closed each of the 4 tabs. Because Never Remember History was in > effect while those home pages fully loaded and while I closed the tabs, FF > should not have remembered their history. Then I changed the preference to > Remember History, causing a new restart. I opened no new tabs, looking only > at Preferences. This time, I found 3 cookies, all from Amazon, all to be > persistent for more than 2 decades. This means that while Never Remember > History was in effect, history was being remembered by FF, and the fact of > FF remembering history was not visible until I elected for FF to Remember > History. I can't reproduce this either. I asked in comment #1 about reproducing this on a clean profile. Did you ever do that and does it reproduce in that case? The one thing I can think of is that there might be issues with cookies being generated by your add-ons or about:newtab which I've seen happening on 40 but not 41, which looks like it might have been fixed in bug 1158208 (which landed for 41).

I did the tangential step because I wanted to see if I could delete cookies by simply finding a cookie file and deleting it in the way I can usually delete other files (I should have explained why I took the step). Since I couldn't read the file when I renamed it to be a *.txt file, I couldn't tell if it contained information FF might need even if there were no cookies, so I don't know if that way of deleting is feasible. The automatic copying was not by me and no other human was using my laptop. I don't know whether the copying was by Gnome, the Files app, or something else, but there was no command or dialog regarding the copying; the copying just happened by itself. In my last run of the test, I did not repeat the tangential step, so it had no effect on the test results. Me: "I visited google.com, amazon.com, yahoo.com, & youtube.com." You: "And then closed the tabs, right?" I don't recall (I probably did then and I did in a later iteration), but that shouldn't matter, since at that point I deleted some cookies, I changed a pref to Never Remember History, FF restarted, I quit FF, I restarted FF, and then found cookies. The intervention of Never Remember means cookies should have disappeared. Running FF being unsupported in root sounds like it should be reported as a bug, if not to change the status of being unsupported, then at least for the simpler solution of telling users. It hasn't been reported, so I expect to do it. The request about trying a new profile was in the context of testing a beta, which I didn't want to do, for other reasons. I didn't try a new profile in version 40.x. However, running the latter test in root, since I usually work in a nonroot account, sounds like a way to use a different and probably fresh profile. In case it's not, I plan to try a new profile, but not now. I should have time to try it soon, maybe this weekend. I have no add-ons unless any were part of the default installation of openSuse 13.2, its installing of FF, or updates (I've allowed all openSuse updates except for Flash, which I refuse to install). At Tools > Add-ons, yielding about:addons, the Extensions and Services pages state that I have no add-ons of those types, the Appearance page lists only Default, which I assume has to stay, and the Plugins page lists five with "Ask to Activate", so I assume they had no effect, and only one with Always Activate, "OpenH264 Video Codec provided by Cisco Systems, Inc.", "to comply with" a spec, so I assume it has to stay in place and stay activated. I don't know about about:newtab or how to check it. From what I get with Firefox Help, it seems to be a feature added since FF version 40. If so, it's not in my FF. I gather OSX is Apple's flavor of Unix, which I gather is decently secure. But if Ubuntu is better than openSuse in this regard, that surprises me, since I thought of Ubuntu as friendlier to users but less secure than other major distros. I hope this isn't a problem introduced by openSuse. Let me know if you think I perhaps should raise this issue on the openSuse bug reporting system. I'll be happy enough with the problem either having been solved in version 41 or if the solution is a relabeling of prefs so that we users know what's actually happening without searching Help or fora. Not really happy, but if someone tells me how to thoroughly delete cookies now and then by going behind the scenes and trashing the file myself without waiting for FF to do it, that's a kludge but I'll tolerate it if ver. 41 does things right. If the solution is a relabeling, I hope that'll be replaced by a full-deletion fix executed by FF based on prefs.

(In reply to Nick Levinson from comment #8) > Running FF being unsupported in root sounds like it should be reported as a > bug, if not to change the status of being unsupported, then at least for the > simpler solution of telling users. It hasn't been reported, so I expect to > do it. It is unsafe, and there are very old issues on file about it in a number of places (random example: bug 95828). > I plan to try a new profile, but not now. I > should have time to try it soon, maybe this weekend. Great, this will be useful. > I have no add-ons unless any were part of the default installation of > openSuse 13.2 profile wouldn't really just be about add-ons, but also about settings and your cookie db. > I don't know about about:newtab or how to check it. It's the default new tab page. When you open a new tab, this is what you see. > I gather OSX is Apple's flavor of Unix, which I gather is decently secure. > But if Ubuntu is better than openSuse in this regard, that surprises me, > since I thought of Ubuntu as friendlier to users but less secure than other > major distros. I hope this isn't a problem introduced by openSuse. Let me > know if you think I perhaps should raise this issue on the openSuse bug > reporting system. At the moment I have no reason to believe this has anything to do with the particular flavour of Linux you're running. The problem is that I also don't know why you're seeing this broken behaviour. It's worked for me on every machine I've tested. > I'll be happy enough with the problem either having been solved in version > 41 or if the solution is a relabeling of prefs so that we users know what's > actually happening without searching Help or fora. Not really happy, but if > someone tells me how to thoroughly delete cookies now and then by going > behind the scenes and trashing the file myself without waiting for FF to do > it, that's a kludge but I'll tolerate it if ver. 41 does things right. If > the solution is a relabeling, I hope that'll be replaced by a full-deletion > fix executed by FF based on prefs. We can't tell you if it's fixed or how we'll fix whatever it is until we figure out what the root of the problem is (or find it's gone in 41). It's clearly not a problem everywhere / for everyone, and so it remains unclear what there is to fix.

Testing Firefox: I worked in a nonroot account, one I usually use, including for all of the above except when I specified root. I created a new profile. FF v40.0.3 opened to an openSuse page. I did not maximize or resize the window. I opened a new tab, which had default content, and used it to go to https://bugzilla.mozilla.org/show_bug.cgi?id=1201354 (the page you're viewing now). I went to Edit menu > Preferences > Privacy. It already said Firefox Will Remember History. I clicked "remove individual cookies". The resulting Cookies dialog listed 7 cookies, of which 2 were to be persistent and 5 were session cookies; the 7 were from <bugzilla.mozilla.org>, <login.persona.org>, & <opensuse.org>; the persistent cookies were from <login.persona.org> & <opensuse.org>; the persistent cookies were to persist into next month or year. I applied Remove All. The dialog no longer listed any cookies. I closed the dialog, using Close. I did not apply the tangential step described above. I visited <google.com>, <amazon.com>, <yahoo.com>, & <youtube.com>, each in its own tab, not opening the next until the previous had finished loading, as indicated by the appearance of the favicon in the tab header. I did nothing with any of the 4 pages. Cookies, checked the same way as at the last time, appeared from 21 domains, totalling 42 cookies, of which 36 were to persist until at least the next day, 1 was to persist but only to a time that was already past while I was doing this test, and 5 were session cookies. I applied Remove Selected to every persistent and possibly-persistent cookie, leaving only 5 session cookies and no cookie that was even possibly persistent. I Closed the dialog, using the bottom Close button (not the title bar "x"). I left all the tabs open. In the same Privacy settings, I changed Remember History to Never Remember History. I okayed the automatic restart. FF opened to an openSusue page. Only 1 tab was open; none of the other tabs that were open when FF began restarting reopened. I applied File > Quit. I again restarted FF. It opened to the openSuse page, with no other tabs open. In the Privacy settings, I changed Never Remember History to Remember History, causing another restart, which I okayed. When it restarted, FF (not me) presented 7 tabs, showing some favicons but not necessarily loading pages until I visited each tab; the tabs were, from left to right, for <opensuse.org>, this page, <about:preferences#privacy>, Google, Amazon, Yahoo, & YouTube, thus remembering the history from before when it was never going to remember it. At <about:preferences#privacy>, I clicked the "remove individual cookies" link (actually twice, but I quickly Closed the Cookies dialog after the first click on the link). I looked at the Cookies dialog (on the second click on the link), which at this point listed cookies from 20 domains, totalling 43 cookies, of which 34 were persistent, 1 was to be persistent but only to a time during this test, & 8 were for the session only. Then, in short, I deleted the new profile, leaving only my one from before this test. One interpretation of this data is that all of the 43 cookies could have been newly created when the tabs reloaded. We can't tell, because I don't know how to find a date-time stamp for a cookie for when it's accepted by the browser. However, even being newly created is a problem, because the tabs are the result of a memory from before Never Remember History was applied, followed by a restart, a quitting, and another restart. That's three opportunities to forget, none of which were exercised (FF should have forgotten as FF began the first restart). We could advise users that forgetting history requires that tabs be closed one by one before quitting or restarting, but that's counterintuitive, because it's contrary to what the Privacy settings page says, which says that it will Never Remember History, after which it restarts and lists an absence of cookies and does not open the old tabs. Given that it is capable of unexpectedly opening those tabs and either introducing old cookies or accepting new cookies as a consequence of an unexpected loading of pages, FF is not Never Remembering, but concealing for revelation later, presumably allowing other websites or domains to read our browser's cookies without our knowing the cookies had even remained. I want to ask at a Mozilla user forum about how to manually delete cookies without reliance on settings until I don't need a result from this bug report, but I'm having trouble with a forum login and am awaiting since yesterday the password-reset email Mozilla twice said it already sent. If I can't use the Mozilla forum any more, I'll likely look for a non-Mozilla forum and hope for the best.

(In reply to Nick Levinson from comment #10) > When it restarted, FF (not me) presented 7 > tabs, showing some favicons but not necessarily loading pages until I > visited each tab; the tabs were, from left to right, for <opensuse.org>, > this page, <about:preferences#privacy>, Google, Amazon, Yahoo, & YouTube, > thus remembering the history from before when it was never going to remember > it. Yes, the "never remember history" thing just automatically starts you in what is essentially "private browsing". It won't remember any history you collect after that. It doesn't remove history or cookies or anything else you created before that. > At <about:preferences#privacy>, I clicked the "remove individual > cookies" link (actually twice, but I quickly Closed the Cookies dialog after > the first click on the link). I looked at the Cookies dialog (on the second > click on the link), which at this point listed cookies from 20 domains, > totalling 43 cookies, of which 34 were persistent, 1 was to be persistent > but only to a time during this test, & 8 were for the session only. Then, in > short, I deleted the new profile, leaving only my one from before this test. > > One interpretation of this data is that all of the 43 cookies could have > been newly created when the tabs reloaded. Well, yes, that is the logical explanation - those cookies were created on your initial visits to those pages, so if you removed them it is likely the sites re-created them when you next visited the sites... > We can't tell, because I don't > know how to find a date-time stamp for a cookie for when it's accepted by > the browser. You could compare the timestamps of the same cookies before and after the removal. They would be different (by however long it took you to restart several times, change preferences, etc.). > However, even being newly created is a problem, because the > tabs are the result of a memory from before Never Remember History was > applied, followed by a restart, a quitting, and another restart. That's > three opportunities to forget, none of which were exercised (FF should have > forgotten as FF began the first restart). As I said above, changing to "permanent private browsing mode" doesn't remove pre-existing history. See e.g. bug 513421. > I want to ask at a Mozilla user forum about how to manually delete cookies > without reliance on settings until I don't need a result from this bug > report Close Firefox completely and remove the cookies.sqlite file in your profile folder. At this point, I don't think there's much of anything we can do in this bugreport, so I will close it. I think Firefox behaves correctly here, but you have a different expectation of what "correctly" means. There are bugs on file for clarifying that distinction, though admittedly they don't seem to be super high priority right now. Either way, I don't think that this bug report currently adds new things that Firefox needs to address.

On Never Remember History being only to forget new history while preserving old history: Then the menu command should be renamed Never Remember New History. My expectation is based on ordinary English. On this, I'm not wrong; FF is. The behaviour may precisely implement what FF's designers intended; but then the command needs to be phrased according to that intent, not something else. Does cookies.sqlite serve no purpose besides storing current cookies? In other words, I won't be making it hard for FF to do anything (besides remember cookies), will I? Do I delete cookies.sqlite-journal also? Any others? Checking the file's date-time stamp is meaningless since cookies.sqlite is a single file containing all of the cookies and maybe (for all I know) other stuff relevant to cookies, so there's not a separate stamp for each cookie. I'm not clear on what's incomplete, but maybe it's better to pursue this at bug 513421, where I've posted. I'm surprised and dismayed it's been six years since that bug's introduction and posters were debating what the critique was even about. I proposed a solution there regarding slowness of removal of voluminous data. I'm adding that bug to the See Also section above.