I've done a bunch of work over the last few days debugging and fixing what turned out to be two distinct problems with the Agas JavaScript. One was a simple failure to deal properly with an unexpected return value from a calculation; all I needed to do was put in place a default value. The other was a bit more complicated; it turned out that it was actually caused by the existence of some places which had Agas map locations specified, but which didn't have appropriate subcategories assigned from the mdtEncyclopediaLocations parent category. Attempts to display any of these places on the map (when, for example, you click-dragged a box to highlight all the places, and caught one of these within the box) would generate an error which make the map stop responding. I've fixed the problem data, and added Schematron to prevent it from happening again. 240 minutes.