Add exceptions for Tab Unloader function

[DRYN07]

There are some domains/urls that I never want to unload (emails, chats, etc). I would suggest an option to add custom URLs that never unload.

I found an option in about:config but maybe this isn't the most convenient way.

[12th-devs]

@DRYN07 There is no setting to add specific URLs, but if you right-click a tab, go to "Tab Unloader Actions" then hit "Prevent tab Unload" you can semi-achieve your desired functionality.

[simonwiles]

This doesn't seem to survive closing and reopening the session, though?

[sethvoltz]

This would be really helpful for certain webapps.