Stopped reverting to default search selection Rated 3 out of 5 stars

I have the latest version installed, which was working fine for a while. For some reason, my search box has stopped reverting to the default search engine, even though I have that option selected. The search box does automatically clear its text, as I have selected. I have Searchbar Autosizer installed as well.

This review is for a previous version of the add-on (0.7.4.1-signed).  This user has 2 previous reviews of this add-on.