yeah i'm finding that when I upload a new activity, then when I click on the activity from the calendar and choose to quick edit and change the name of the activity and save, when calendar tries and loads it hangs, but if then click on Plan->Calender" again it loads.
Now I find EVERY time I try and access the calendar it is stuck at "loading" with the rotating arrow. I now have to click the "refresh" button each time on the Web Browser to be able to get the Calender to load properly. BTW my Web Browser is Windows IE version 10.