Fixes #13637.  Add opacity to firefox to make DIV's look disabled in a11y mode.
Fixes #13637.  Add opacity to firefox to make DIV's look disabled in a11y mode.

git-svn-id: 674a2d6b1e32e53f607eb824547723f32280967e@26285 560b804f-0ae3-0310-86f3-f6aa0a117693

redaktor/deliteful