This is a tracking bug for mix-blend-mode
Created attachment 8413008 [details] [diff] [review]
set runtime flag to true
try build: https://tbpl.mozilla.org/?tree=Try&rev=c1b6086f29d8
Added in the release notes with the wording "mix-blend-mode enabled by default"
layout.css.mix-blend-mode.enabled = true by default, so verified as fixed on Firefox 32 Beta 5 (buildID: 20140807212602) under Windows 7 64bit, Mac OS X 10.9 and Ubuntu 64bit.