Bug 120317 Set "dimension" property to 3D in "properties" view, error appears in layout editor.
Description: Set "dimension" property to 3D in "properties" view, error appears in layout editor. Steps to reproduce: 1. Add a 2D chart in property editor. 2. Set its dimension property to "three-dimension" in properties view. 3. Error appears in chart.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/metadata/ExtensionLoader.java
* 
		 * @param elementTag
		 *            the element tag
		 * @throws MetaDataException
		 *             if error encountered when adding the element to metadata
		 *             dictionary.
		 * @throws ExtensionException
		 *             if the class some attribute specifies can not be
		 *             instanced.
		 */
		abstract void loadElement( IConfigurationElement elementTag )
				throws MetaDataException, ExtensionException;
		/**
		 * Loads one property definition of the given element.
		 * 
		 * @param elementTag
		 *            the element tag
		 * @param propTag
		 *            the property tag
		 * @param elementDefn
		 *            element definition
		 * 
		 * @return the property definition
		 * @throws ExtensionException
		 *             if the class some attribute specifies can not be
		 *             instanced.
		 */
		abstract ExtensionPropertyDefn loadProperty(
				IConfigurationElement elementTag,
				IConfigurationElement propTag, ExtensionElementDefn elementDefn )