Bug 207825 Crosstab gives wrong default for Totals on Count
xtab/org.eclipse.birt.report.item.crosstab.core/src/org/eclipse/birt/report/item/crosstab/core/de/internal/DimensionViewTask.java
if ( crosstab != null )
			{
				doPreRemove( levelView );
			}
			levelView.getModelHandle( ).drop( );
			if ( crosstab != null )
			{
				validateFilterCondition( );
				validateSort( );
			}
		}
		catch ( SemanticException e )
		{
			if ( needTransaction )
			{
				stack.rollback( );
			}
			throw e;
		}
		if ( needTransaction )
		{
			stack.commit( );
		}
	}
	/**
	 * Removes a level view at the given position. The position index is 0-based
	 * integer.
	 * 
	 * @param index
	 *            the position index of the level view to remove