incompatible with FF 20.0 Beta?!? Rated 4 out of 5 stars

It looks like SiteDelta either is incompatible with FF 20.0 or there is a side effect.
Often (but not reproducible always) a right click in the side bar of SD opens the clicked site (independent of changes).
This also occurs, when more than one site is marked and right clicked (to choose 'check for changes').
Hmmm, no life on the homepage? Hopefully site delta is still alive..., Andreas Schierl?
If you can tell me something about this behavior, I'll change the rating. But in a time of more and more 'dying addon's' I use this method to 'mark' them as dead.

This review is for a previous version of the add-on (0.13.1). 

I just installed FF 20 Beta, but could not reproduce the behaviour you described. It works fine for me.