Why don't you allow a choice of new tab or same tab each time you run a custom search with a custom seach engine? It shouldn't be one or the other.

Subject: Firefox Search Bar – “Search in New Tab” right-click option I frequently use Firefox's separate Search bar with several custom search engines. Currently, I can open a search in a new tab by clicking my mouse wheel and then the arrow button, but this functionality isn't obvious from the interface. With the about:config...browser.search.openintab, I can make it do new tabs or current tabs, but I don't get a CHOICE on each new search. I suggest adding “Search in New Tab” as the first item on the right-click menu for the Search bar's arrow button. At present, that context menu prominently offers “Pin to Overflow Menu,” which is easy to select accidentally but doesn't provide the much more natural search-related choice. And it's a terrible choice for accidental clicking because it undoes your menu bar, requiring a fix. This would allow mouse-only users to choose at the time of each search whether to replace the current tab or open the search in a new tab, without changing a permanent preference or using a keyboard modifier. The option to "Open in New Tab" is normal behavior for menu items. It should be the same for searches in the custom search bar. Thank you Thomas