I got this message after running a few searches: "The maximum number of historical concurrent system-wide searches has been reached." It seems that closing the window or navigating away from the page does not end the search. Is there a proper way to stop a search/query?
If you've already navigated away from the page (or closed it) you can locate the search using "Jobs". Click on "Jobs" in the upper right hand corner of UI, add some search terms to the field to locate your search job, then click "Delete".
Very simple: use the "stop" icon (white cross; red circle).