The Mozilla Firebird “Flash Click To View” seems to have issues with recent versions of Firebird nightlies and it has not been updated in a while.

I noticed over on mozdev.org’s Extension Room that some kind soul has written his own version: http://www.suteki.org/downloads/flashblock-0.3.xpi.

The Flash Block notice with this version uses softer colors and fonts and doesn’t stand out as much on your typical page.