Have you tried this?

Type about:preferences#privacy<enter> in the address bar. The button next to History, select Use Custom Settings.

Turn on Remember My Browsing And Download History At the bottom of the page, turn on Clear History When Firefox Closes. At the far right, press the Settings button. Turn on Cache and Form And Search History and whatever else you want.

Data stored in local storage is meant to be persistent and isn't cleared automatically unless you clear this data when you close Firefox.

If you do not want data stored locally for some websites then you can use Private Browsing mode. Otherwise you would have to clear this data yourself in the data manager.

FredMcD said

Have you tried this? Type about:preferences#privacy<enter> in the address bar. The button next to History, select Use Custom Settings. Turn on Remember My Browsing And Download History At the bottom of the page, turn on Clear History When Firefox Closes. At the far right, press the Settings button. Turn on Cache and Form And Search History and whatever else you want.

Sorry I should have been clearer: I want to have the data be deleted while the Firefox session is still active.

cor-el said

Data stored in local storage is meant to be persistent and isn't cleared automatically unless you clear this data when you close Firefox. If you do not want data stored locally for some websites then you can use Private Browsing mode. Otherwise you would have to clear this data yourself in the data manager.

Do you know if it is a technical limitation of Firefox that prevents this data from being deleted automatically, even though it can be done manually?

WillW said

cor-el said

Data stored in local storage is meant to be persistent and isn't cleared automatically unless you clear this data when you close Firefox. If you do not want data stored locally for some websites then you can use Private Browsing mode. Otherwise you would have to clear this data yourself in the data manager.

Do you know if it is a technical limitation of Firefox that prevents this data from being deleted automatically, even though it can be done manually?

There is no technical limitation on removing data. However, there also is no feature to remove a site's data automatically simply because you closed a tab. The closest thing, as cor-el mentioned, is to use the site in a private window and close all private windows when you want to flush the temporary storage used by private windows.

jscher2000 said

WillW said

cor-el said

Data stored in local storage is meant to be persistent and isn't cleared automatically unless you clear this data when you close Firefox. If you do not want data stored locally for some websites then you can use Private Browsing mode. Otherwise you would have to clear this data yourself in the data manager.

Do you know if it is a technical limitation of Firefox that prevents this data from being deleted automatically, even though it can be done manually?

There is no technical limitation on removing data. However, there also is no feature to remove a site's data automatically simply because you closed a tab. The closest thing, as cor-el mentioned, is to use the site in a private window and close all private windows when you want to flush the temporary storage used by private windows.

Okay I understand. It's disappointing though because it means that if websites are using trackers that are not known or not detectable by Firefox, then there is no way to prevent that tracking on a per-session basis without constantly closing and re-opening browser windows.

The only other option is to block all data from these websites from being set in the first place, which is similarly impractical because it would prevent you from logging into the website at all.