If you don't mind doing the search again you can click the dropdown list at the top to see the recent reference searches you did. You can also do right click -> contents -> copy ; then paste into a text file and you get a bunch of text that you can manipulate.
I do mind doing the search again. because I want to quickly go back to the old search and start clicking on some of the links, but they are gone
It seems a shame that I need to rerun the same search and wait for the results when that same search was already done recently.
It would be sweet if I could just click on a tab and have them back quickly

Maybe I could even have the memory where I left the cursor in each tab, to put me back in context?
This happens often when looking at all refs of funcA(), but then you see one instance of funcA() calling funcB(), so you want to see where else funcB() is called. When you are done with funcB() and want to go back to funcA(), it would be useful to see where you left off.