In the sample application, the method "piovtchart.pivotengine.populate()" was called asynchronously on every UI operation. When performing the filter operation in pivot scheme desinger the null reference exception was thrown.
Steps to reproduced:
Step 1: Run the attached sample.
Step 2: Drag the Date field to filter area.
Step 3: Perform filtering operation.
Note: The exception occur while doing the filter operation.