The Hangs, seems to happen all the time in report writer when I am trying to write a query. It usually happens when I am in the SQL tab trying to write an SQL statement, and it will "hang" and take 1 processor up to 100% and after a few minutes it will do one of 2 things, it either comes back, or it just stays there, and I kill the task. It's running on a VM that we have devoted 4 processors and 4G of memory.
I've also noticed that sometimes the query will not run unless I bounce thru the tabs a few times, as it doesn't produce the results after I change a query.