Can you upload an example, I'm sure that would help others.
I've also "borrowed" the Reports tab idea from the QT app.
One of the issues I had which may or may not be related was down to the conditional formula.
The demo app has less than 10 metrics. When you get to 10 there is a problem.
=SubStringCount(Concat(%metricsNo, '|'), 1)
=SubStringCount(Concat(%metricsNo, '|'), 10)
When you select metricNo 10 both of these expressions will evaluiate to true.
Because "1" is a substring of "10"
Similar issues can occour in the dimensions if you use field names with the same string.
I got around this using
=Match('My Dimension Name',$(=vDimensions))>0
=Concat( chr(39) & %dimension & chr(39) ,',')
=Concat( chr(39) & %metricsNo& chr(39) ,',')