I've released a major update to Keyword Search that resolves ALL coexistence problems with Tab Mix Plus. It should also fix all the strange behaviors people were seeing with regards to searches happening in incorrect tabs.

I've also added support for setting a separate search engine for the context menu, as well as fixed some visual problems on about:home.

You can get it here, or you will be automatically updated.

https://mike.kaply.com/2015/03/12/major-update-to-keyword-search/