I fixed the locations search form, so a search does not cause your criteria to be deleted 
Should be a much more pleasant experience searching now!
(cleanup: remove commented code 路 paviliondev/discourse-locations@0153eab 路 GitHub)
thanks for @jrgong鈥檚 report and for being patient.
this is a free, presently unmonetized plugin, so it鈥檚 tough to justify a lot of work on it.