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
*/
	void setExtends( String base )
	{
		assert !isBuilt;
		extendsFrom = base;
	}
	/**
	 * Sets the "supports user properties" attribute.
	 * 
	 * @param flag
	 *            True if the element allows user-defined properties, false
	 *            otherwise.
	 */
	void setSupportsUserProperties( boolean flag )
	{
		assert !isBuilt;
		supportsUserProperties = flag;
	}
	/**
	 * Gets the name of the parent element, if any. The parent element is the
	 * one that this element extends.
	 * 
	 * @return The name of the base element, if any.
	 */
	public String getExtends( )
	{
		return extendsFrom;
	}
	/**
	 * Gets the java class of this element.