Sometimes when the Enterprise Dashboard window is refreshed it takes long time to load it. Restarting Enterprise Dashboard resolves issue for sometime but after few hours face the issue again.
Loading many registries data for the past 30 days is taking time and causing the issue.
Release : 10.2
Component : CA Application Test
If any one facing the same issue, please open a new case and refer DE429547 and request a patch. The patch will set the default time period of the reports to last day and that should resolve the issue.
Manually changing the time period to 1 day/1 Week in the Enterprise Dashboard-->Total Transactions/Virtual Services for non performance VSE's should also resolve the issue.