How do i prevent SearchCanvas from appearing when a new window is opened on firefox?

so i have mozilla firefox and recently have been having problems with the search engine SearchCanvas , which i REMOVED from my search engines but continues to appear! xO and, i want to know if there is a way i can prevent SearchCanvas from appearing when i open a new window in mozilla firefox. even if i click the facebook icon on my yahoo toolbar. searchcanvas redirects me to a page with links to fb, which even clicking on those, takes me to SearchCanvas, AGAIN! pleaseeee can someone help with this... abomination..? thankyou :)