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
if ( source instanceof SlotHandle )
		{
			SlotHandle slot = (SlotHandle) source;
			Object[] array = new Object[slot.getCount( )];
			for ( int i = 0; i < array.length; i++ )
			{
				array[i] = slot.get( i );
			}
			return cloneSource( array );
		}
		if ( source instanceof StructureHandle )
		{
			return ( (StructureHandle) source ).getStructure( ).copy( );
		}
		return null;
	}
	/**
	 * Drops source data
	 * 
	 * @param source
	 *            source to drop
	 */
	public static void dropSource( Object source )
	{
		DeleteCommand command = new DeleteCommand( source );
		if ( command.canExecute( ) )
			command.execute( );
	}
	/**
	 * Gets handle of target