Bug 167542 A parameter group isn't deleted after moving it to another parameter group through DND
Drag a parameter group and drop it to another one is a "move" operation, which cuts the source and pastes to the destination. But the source one isn't deleted in such operation while the parameters in the group are all deleted.
UI/org.eclipse.birt.report.designer.core/src/org/eclipse/birt/report/designer/util/DNDUtil.java
* Pastes elements. Includes transaction.
	 * 
	 * @param transferData
	 *            single or multiple transfer data, every data must be an
	 *            instance of <code>DesignElementHandle</code> or
	 *            <code>DesignElement</code>
	 * @param targetObj
	 *            container or sibling. Copy position is after the sibling or
	 *            the last in the container
	 * @return paste result
	 */
	public static boolean copyHandles( Object transferData, Object targetObj )
	{
		if ( getColumnHandle( transferData ) != null )
		{
			return copyColumn( getColumnHandle( transferData ),
					targetObj,
					false );
		}
		int canContain = handleValidateTargetCanContain( targetObj,
				transferData,
				true );
		int position = calculateNextPosition( targetObj, canContain );
		if ( position > -1 )
		{
			targetObj = getDesignElementHandle( targetObj ).getContainerSlotHandle( );
		}
		return copyHandles( transferData, targetObj, position );
	}
	/**