This is how the Firefox extension works (Win and Mac)

Of course, Linux is fine as well!

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  The extension after logging in (as 'demo' in this case). Notice this profile's default search engine in brackets. The default search engine is used if no search engine gets selected.

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  You can simply type a certain kind of thing you want to search for ('video' in this case). This brings up all the search engines that have been tagged accordingly.

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  If you know the name of the search engine you want to use, just type the first letters. Your most often used search engines will show up first, so most of the times you just have to type one or two letters and hit return.

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  Have you noticed how the search box turned from red to green? This means that it's time to type in your query now. Then hit return again. Want another search engine? Hit [escape] or click on the little red arrow and all goes back to red.

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  After your search, you see your last query and, in brackets, the search engine that is selected. This is what would happen if you clicked on the search box again (or hit ctrl+k): The engine name is removed, and the query gets selected. That lets you simply overwrite or modify it.

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  One of the biggest timesavers: If you choose another search engine, the search box will get pre-filled with your last query (it gets selected, so you can overwrite it if you want something else). With this, querying multiple engines for what you are looking for becomes super-fast.

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  One last thing: You can add any search field you encounter to your profile via the context menu and start using it right away. Later, you can share it with others at lookpicking.com.

Want more details? Go here!