Rated 2 out of 5 stars

The first letter always appears twice whenever I type in webpage search boxes or reply boxes. Please get it fixed.

This review is for a previous version of the add-on (0.5). 

This addon gets active only when text is selected. Maybe issue caused by other addon or there is interference with other addons.
If you still think that issue is caused by addon than please provide more details (addon version, browser version, OS, steps etc), would appreciate if support site will be used for bug reports.