search text rather than opening external link

I'm struggling to disable this behavior of firefox. When I type "something: text", it's opening a pop-up asking "Open link with System Handler?". I would rather just search the internet for "something: text". How can I do that? I've tried to play with parameters like network.protocol-handler.expose.something network.protocol-handler.app.something network.protocol-handler.external.something network.protocol-handler.warn-external.something but didn't manage to do it