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When I use Firefox I often have many tabs and many windows open (even more so now that they have panorama). I often use the session restore feature because I don't want to lose all my open windows when installing a new add-on or restarting my computer for updates.

However, with so many tabs open it takes a really, really long time for Firefox to load all the tabs.

I'm looking for an extension that will open a placeholder tab for all of the websites on session restore but won't actually load the page until I click on that tab to bring it to focus.

Basically, it would look like I had 40 tabs open, but until I click on that tab, it won't be taking up any more memory than an about:blank page.

Giacomo1968
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rhololkeolke
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3 Answers3

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You could use BarTab, but I find it doesn't work too well with Firefox 4/5.

Another more reliable way is to use the new about:config property, browser.sessionstore.max_concurrent_tabs.

Go to about:config in firefox and search for browser.sessionstore.max_concurrent_tabs. Set the integer value to 0.

Now when you start up Firefox, only the first open tab will be opened. All the rest need to be clicked/focused on before they are actually loaded.

enter image description here

Steve
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As of March 2024, Firefox Version 124, that is default behavior for Firefox (it has been there for many many years, see the Edit). After a restart, Tabs will only be loaded once you actually click on them. This works on Windows, and it should work the same way on Mac or Linux (although I cannot test this).

So, go to about:support and click on "Refresh Firefox". that should eliminate any user setting which could interfere with such behavior.

If that should not help, try uninstalling and reinstalling.

EDIT:

In this thread from 2020 a user asks to disable the feature, and in this other thread from 2017 a related question is asked: which means that the functionality has been there for many years. More interestingly, in about:config there are two distinct flags:

  • browser.sessionstore.restore_on_demand when set to false (default is true), will load all tabs on startup.
  • browser.sessionstore.restore_pinned_tabs_on_demand will do the same only for pinned tabs.

So, by using pinned tabs you can have some of your tabs auto-load, while the others will not load on startup.

1NN
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0

BarTab will do this.

BarTab can intercept when tabs are loaded in the background or restored after a browser restart and will only load the content when the tab is actually visited. It also allows you to free memory by unloading already loaded tabs, either manually or automatically.

Giacomo1968
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slotishtype
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