Firefox Instantfox addon problems

I use instantfox addon and it merges search into the adressbar. It works fine if I pick my search with the arrows on the keyboard but if I try to select search with the mouse it does only search the few letters I had written.

If I use the same addon on Palemoon browser it works just fine.

Anyone know a solution to this? Thanks

I have the same problem. In addition, the last letter of a search topic is truncated. I tried using changing the default search engine and using "g" for Google to see if that would solve the problem, but it makes things worse. If I type g followed by a space and my search topic, when I hit enter I am directed to a blank page.