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
* Does insert and paste column to table/grid
	 * 
	 * @param transferData
	 *            copy data of column
	 * @param targetObj
	 *            target column of table/grid
	 * @return paste result
	 */
	public static boolean insertPasteColumn( Object transferData,
			Object targetObj )
	{
		if ( getColumnHandle( transferData ) != null )
		{
			return copyColumn( getColumnHandle( transferData ), targetObj, true );
		}
		return false;
	}
	protected static ColumnBandData getColumnHandle( Object transferData )
	{
		if ( transferData instanceof ColumnBandData )
		{
			return (ColumnBandData) transferData;
		}
		if ( transferData instanceof Object[]
				&& ( (Object[]) transferData ).length == 1 )
		{
			return getColumnHandle( ( (Object[]) transferData )[0] );
		}
		return null;
	}