Comment 8 for bug 1478173

I have not had a change to test this on older Ubuntus with the new nightly firefox yet but I can confirm this is a issue with 15.04 & 15.10 . And since when this hits in the latest firefox (that will be shipped on nearly all supported Ubuntu builds) this fix may need to be tested and applied to older and newer builds of Ambaince Themes (EG one in 14.04 , 12.04 etc.) I am not sure yet however.