Bug 183579 Model need hold on DimensionConditionHandle and DimensionJoinConditionHandle signleton or overwrites the equals and hashcode method
The Dataset Joint Editor need join two Editparts which have the same model. But the DimensionConditionHandle and the DimensionJoinConditionHandle are create a new instance erery time when I get them. So model need hold on them signleton or overwrites the equals and hashcode method.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/MemberRef.java
assert member[0].isList( );
					list = (List) struct.getProperty( module, member[0] );
					return list;
				case PROPERTY_LISTn_MEMBER_LISTn_MEMBER :
				case PROPERTY_LISTn_MEMBER_MEMBER :
					
					return null;
			}
			return list;
		}
		
		Structure struct = (Structure) element.getProperty( module, propDefn );
		if ( struct != null && member[0] != null && member[0].isList( ) )
			return (ArrayList) struct.getProperty( module, member[0] );
		return null;
	}
	/**
	 * Indicates whether this member reference points to a list.
	 * 
	 * @return true if points to a list.
	 */
	public boolean isListRef( )
	{
		switch ( refType )
		{
			case PROPERTY :
				return propDefn.isList( );
			case PROPERTY_MEMBER :
			case PROPERTY_LISTn_MEMBER :