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
return false;
			}
			return true;
		}
		if ( selection instanceof SlotHandle )
		{
			SlotHandle slot = (SlotHandle) selection;
			DesignElementHandle handle = slot.getElementHandle( );
			return slot.getContents( ).size( ) > 0
					&& ( handle instanceof ListHandle || handle instanceof ListGroupHandle );
		}
		if ( selection instanceof ColumnHandle
				&& ( (ColumnHandle) selection ).getRoot( ) != null )
		{
			int columnNumber = HandleAdapterFactory.getInstance( )
					.getColumnHandleAdapter( selection )
					.getColumnNumber( );
			Object parent = ( (ColumnHandle) selection ).getContainer( );
			if ( parent instanceof TableHandle )
			{
				return ( (TableHandle) parent ).canCopyColumn( columnNumber );
			}
			else if ( parent instanceof GridHandle )
			{
				return ( (GridHandle) parent ).canCopyColumn( columnNumber );
			}
		}
		return selection instanceof ReportItemHandle
				|| selection instanceof DataSetHandle
				|| selection instanceof DataSourceHandle