Rated 3 out of 5 stars
That is confusing that left click and middle click actions are actually messed up:
when you click any link in the browser with a left click - you will get it opened and active in any case.
And middle-clicking the links lets you open them in the background (without activating the newly created tab).
Please, change the 2 actions vice versa.
That is also confusing because when you middle-click on some menu-item in the context menu - the menu doesn't get hidden (which is right), but since the opened tab gets activated immediately - it's absolutely confusing to see the context menu shown in the new tab, though it is actually related to another tab.
But the current behavior lets you do a quick overview of the newly opened tab with the search, so you can read it and decide whether to search somewhere else (with just 1 extra click) or not, so this actually may be useful.
So I suggest you to add an option and let users choose the state they prefer more.