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
* <p>
	 * <strong>property </strong>[.member] <br>
	 * property. <strong>member </strong>.member <br>
	 * property.member. <strong>list[n] </strong>[.member] <br>
	 * 
	 * property. <strong>list[n] </strong>[.member] <br>
	 * property.list[n].member. <strong>list[n] </strong>[.member] <br>
	 * property.list[n]. <strong>member </strong>.member
	 * 
	 * @param module
	 *            the module
	 * 
	 * @param element
	 *            the element from which to retrieve the structure
	 * @return the value of the referenced structure
	 */
	public Structure getStructure( Module module, DesignElement element )
	{
		if ( propDefn.isList( ) )
		{
			ArrayList list = (ArrayList) element.getProperty( module, propDefn );
			if ( list == null )
				return null;
			switch ( refType )
			{
				case PROPERTY_LISTn :
				case PROPERTY_LISTn_MEMBER :
					return getStructure( list, 0 );
				case PROPERTY_LISTn_MEMBER_LISTn :
				case PROPERTY_LISTn_MEMBER_LISTn_MEMBER :