When you are creating dashboard, the Not Currently Shown fields of the reports added to dashboard cannot be seen in the connections tab for mapping. The report which is under the select source shows only the fields which are in the rows of the report.
Reproducing the Issue
Steps to reproduce:
1. Go to Analysis work center access Dashboard view
2. Click on New Dashboard
3. Add the reports to dashboard (Eg: Campaign Activities and Campaign Open and Closed Activities)
4. Click on next and navigate to connection tab
This is system designed behavior.
The Not Currently Shown fields of the source report are not supported in dashboard connections tab. This is a known restriction.
KBA , AP-RC-ANA , C4C, ByD, Travel: Analytics Tools & Frameworks , Product Enhancement