Bug 145698 Name change won't enable "restore property" button
Steps to reproduce: 1.New a report, extends lib.label 2.Choose the label, switch to property editor, chang its name to "aa" 3.Choose the label again Expected result: "Restore property" button is enabled Actual result: "Restore property" button is grayed out
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/ModuleHandle.java
{
		ElementPropertyDefn propDefn = module
				.getPropertyDefn( CONFIG_VARS_PROP );
		if ( configVar != null && StringUtil.isBlank( configVar.getName( ) ) )
		{
			throw new PropertyValueException( getElement( ), propDefn,
					configVar,
					PropertyValueException.DESIGN_EXCEPTION_INVALID_VALUE );
		}
		if ( configVar != null
				&& findConfigVariable( configVar.getName( ) ) != null )
		{
			throw new PropertyValueException( getElement( ), propDefn,
					configVar.getName( ),
					PropertyValueException.DESIGN_EXCEPTION_VALUE_EXISTS );
		}
		PropertyCommand cmd = new PropertyCommand( getModule( ), getElement( ) );
		cmd.addItem( new CachedMemberRef( propDefn ), configVar );
	}
	/**
	 * Adds a new embedded image.
	 * 
	 * @param image
	 *            the image to add
	 * @throws SemanticException
	 *             if the name is empty, type is invalid, or the same name
	 *             exists.
	 */
	public void addImage( EmbeddedImage image ) throws SemanticException
	{