When you select text in the Firefox web browser and right-click afterwards, you get a custom context menu with options to search Google for the selected term. That option can be quite handy to quickly find information about text on a website without having to type the text in a search form, or having to copy and paste it.
The question recently came up if it is possible to change the right-click context menu search engine from Google to another search engine. After some tweaking and testing, I found out that it is directly tied to the default search engine in Firefox.
Please note that there are two default search engines in the browser. First the search engine that is used when you enter text in the address bar of the browser, and then the search engine that is used when you use the search form to search on the Internet.
Update: Mozilla changed the way search is handled in Firefox in recent versions. Everything is handled by one search engine by default now in the browser. This does not change how the context menu search works though as it is still linked directly to that search engine.
Firefox opens a Google search results page when you select “Search Google for” from the Firefox right-click menu. The search engine context menu entry is linked directly to the search engine of the search form in Firefox.
When you change that default search engine, you change the search engine of the right-click menu as well.
The search form in my version of Firefox is hidden, and I’m sure that I’m not the only user who is only searching via Firefox’s address bar. You need to unhide the search form and switch the search engine in that form to change the right-click context menu search engine as well.
Update: In recent versions of Firefox, it is possible to manage search engines by loading about:preferences#search.
This is done by selecting Alt-key > View > Toolbars > Customize, and dragging and dropping the search engine to a toolbar of the browser.
There is no option to quickly change between search engines, especially not if you hide the search form by default.
The Firefox add-on Context Search comes to the rescue. It can be used to select one of the installed search engines directly to the Firefox right-click menu.
The extension displays all installed search engines in the context menu, handy if you regularly switch between search engines in the browser.