Bug 163018 An error extension will lead the report contain chart can't be opened and can not new a report.
Details: An error extension will lead the report contain chart can't open In org.eclipse.birt.report.tests.model has an error extension. When run the birt use workbenck, the report contain chart can't be opened and it can not new a report.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/metadata/ElementDefn.java
* description of user-visible elements.
	 * 
	 * @return True if this is an invisible abstract element, false if this is a
	 *         concrete, user-visible element.
	 */
	public boolean isAbstract( )
	{
		return abstractElement;
	}
	/**
	 * Gets the predefined style for this element.
	 * 
	 * @return The predefined style .
	 */
	public String getSelector( )
	{
		return selector;
	}
	/**
	 * Gets the parent element. This is the element that this element extends.
	 * 
	 * @return Returns the parent element.
	 */
	public IElementDefn getParent( )
	{
		return parent;
	}
	/**
	 * Adds the name of a style property that should be made visible to this
	 * element type. Must be done while creating the element type.