events won't load when selecting tree in Infrastructure view

sometime recently, my tree filtered events view quit loading. no error, just like it doesn't execute. when looking at the url, it doesn't request the event_matrix routine. and i can't append it to the end of the url to force it to load.

i can to to the main events page and all events load..but from infrastucture on any focused tree, when you click details to see events option on left side of screen, it won't work.