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 memberDefn != null;
		refType = PROPERTY_LISTn_MEMBER;
		index[0] = n;
		depth = 1;
		member[0] = memberDefn;
	}
	/**
	 * Reference to the identified member of the structure at the nth position
	 * within the top-level list.
	 * <p>
	 * property.list[n].member
	 * 
	 * @param prop
	 *            the property definition
	 * @param n
	 *            the list index
	 * @param memberDef
	 *            the definition of the member
	 */
	MemberRef( ElementPropertyDefn prop, int n, StructPropertyDefn memberDef )
	{
		propDefn = prop;
		assert propDefn != null;
		assert propDefn.getTypeCode( ) == IPropertyType.STRUCT_TYPE;
		assert propDefn.isList( );
		assert n >= 0;
		assert memberDef != null;
		refType = PROPERTY_LISTn_MEMBER;
		index[0] = n;
		member[0] = memberDef;