Development Blog

Firebug 1.12.5

Firebug team released Firebug 1.12.5. This version improves a workaround that solves Firefox tab switching and Firebug activation problem (due to a platform bug). See the detailed description of related changes below.


Firebug 1.12.5b1 has also been released to update users on AMO beta channel. This version is exactly the same as 1.12.5


Firebug 1.12.5 is compatible with Firefox 23 – 26

Firebug 1.12.5 fixes 4 issues.


Script Panel Activation

Since version 1.12.4, Firebug doesn’t pause the underlying Firefox JavaScript debugger engine (JSD) when the user is switching Firefox tabs. This avoids long tab switching times since JSD.pause/unPause is broken (it’s the platform bug). This means that Firebug with active Script panel can slow down the browser even if it’s on a background Firefox tab.

The user can see related warning message on disabled Script panel and also (if the Script panel is already enabled) within the Console panel.

Console Panel Warning

Script Panel Warning

Enabling the Script panel causes a Firefox slow-down due to a platform bug. This will be fixed with the next major Firefox and Firebug versions.

If you have the Script panel disabled, the platform bug doesn’t affect your browser experience.

Start Button Icon

In order to make it easier for the user to see that there is an active Firebug instance in the background we introduced a new state for the Start Button Icon (read more about the Start button).

Firebug is active on the current tab.
Firebug is not active on the current tab.
Firebug is active on a background tab (this is the new state).

Start Button Tooltip

Start button tooltip has also been improved. You can use it to see how many Firebug instances are currently active (you’ll see the number even if Firebug is not active on the current tab).

The Screenshot shows that there are 3 active Firebugs in the browser (and the icon indicates that one of them is on the current page).

Shutdown Firebug

Finally, in order to quickly shutdown all Firebug instances at once and ensure that the underlying Firefox debugging engine (JSD) is deactivated (not slowing down the browser anymore), you can pick Clear Activation List from the Start button context menu.


Please post feedback in the newsgroup, thanks.

Jan ‘Honza’ Odvarko


Comments are closed.