Then update the theme to Firefox 15 Oxygen KDE -one of the best themes currently available to integrate the appearance of Firefox into KDE- stop working.
The quickest solution to reusing the theme in the latest version of Firefox was disable add-on compatibility checking from the browser. There are extensions for this, although it is something that is extremely easy to achieve through the advanced preferences of Firefox.
To disable compatibility checking for Firefox 15 add-ons, you must first open a new tab and type about: config. We promise the browser that we will be careful as we dig into its bowels, ensuring that we are not very pocatraça.
Once inside we click secondary and in the popup menu we select New → Logical.
In the window that opens we enter extensions.checkCompatibility.15.0.
And then we select the value «false».
We accept the changes. Now just go to the settings section of the add-ons to make sure that those that were disabled / blocked are not compatible with the new browser version they can be reactivated.
It should be noted that this is an inappropriate method to use our add-ons and that it would be best to wait for them to be updated by their developers. Although if one cannot wait, or needs some specific supplement to work with, it is well worth it.
More information – Integrates the appearance of Firefox in Kubuntu, Firefox 15 now available in Ubuntu 12.04