(1) Explain your problem, don't simply post "This isn't working". What were you doing when you faced the problem? What have you tried to resolve - did you look for a solution using "Search" ? Has it happened just once or several times?
(2) It's also good to get feedback when a solution is found, return to the original post to explain how it was resolved so that more people can also use the results.
WBS Summaries will capture the start and end dates from all activities within the WBS Group. LoE (hammocks) allow you to select which activities drive the start and end dates, and they do not need to be within the same WBS group either.