See the attached image. Steps to reproduce: 1. I checked the checkboxes 'Product' and 'Price'. The Product field added to row labels, and price to values. 2. Unchecked the 'Price', the price field removed from the pivot. 3. Unchecked the Product, doesn't remove the products from the pivot.
It happens when you change the distinct values selection several times. The PivotGrid disappears after the exception is thrown. I managed to reproduce it in the demo by repeating this action around ten times.