Screengrab 0.95 will be the FF3 compatible version.
It consists of a couple of tweaks to moz chrome changes that snuck in at the last minute.
All should be good soon.

I’m also working on a new release that should resolve a few of the long-standing complaints that people have with Screengrab! and will add some nifty new features.

See the Google Code issues page for a list of what I’m working on for the new release.

This isn’t exhaustive, and none of it is guaranteed to happen by the next release.

The biggest changes going in are under the covers and involve using Java AND the Canvas to always accurately capture what is in the page.