Just an update,
I found out that my problem is caused by the "Tab Mix Plus" Add-on. After disabling it, my customizations remain after a firefox restart.
Will keep it like this for now. Sorry for my mis-posting...
Just an update,
I found out that my problem is caused by the "Tab Mix Plus" Add-on. After disabling it, my customizations remain after a firefox restart.
Will keep it like this for now. Sorry for my mis-posting...