Users need to increase to more than the maximum of 15 charts of On-Demand multi-metric views.
Don't see any corresponding attribute in the Performance Center Global Attribute page.
Increasing above 15 in the report setting generates an error.
It might help when you increase the "OnDemand.MaxItemsSelected.Limit" Parameter from 15 to a higher value... not tested so far, did anyone test it ?
Re-tested that with same result:
Retrieving data ...