Rated 1 out of 5 stars

Addons like this are why Firefox has a bad rep.
use the built-in error console for that. Click on Firefox > Web Developer > Error Console, or use Ctrl-Shift-J, to open it in the browser. Locate the filter at the top right and paste TypeError: can’t access dead object into it. If you see results, one of your add-ons is trying to access memory that has been cut by the browser.

This review is for a previous version of the add-on (0.7.2.0.1-signed.1-signed). 

This seems happen after restore crash sessions.Any way, we will fix them.Thanks for the information.Wind