title: determine clear value event in PivotTableAfterValueChange
body: <p>I have an excel pivotgrid (connected to writeback enabled SSAS cube).</p>
  
  <p>When i clear contents (select range &amp; press DEL) of cells it fires PivotTableAfterValueChange event, but Value property of affected cells stil contained old value.</p>
  
  <p>Moreover, CellChanged property stays xlCellNotChanged.</p>
  
  <p>Is there any way to determine such clear event, to override existing behaviour?</p>