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
}
	/**
	 * Adds an invisible property to the list.
	 * 
	 * @param propName
	 *            the property name
	 * @param propVisibility
	 *            the level that how to show the property in the property sheet.
	 */
	public void addPropertyVisibility( String propName, String propVisibility )
	{
		if ( propVisibilites == null )
			propVisibilites = new HashMap( );
		propVisibilites.put( propName, propVisibility );
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.model.api.metadata.IElementDefn#isPropertyReadOnly(java.lang.String)
	 */
	public boolean isPropertyReadOnly( String propName )
	{
		IPropertyDefn propDefn = getProperty( propName );
		if ( propDefn == null )
			return true;
		String visibility = getPropertyVisibility( propDefn.getName( ) );
		if ( READONLY_IN_PROPERTY_SHEET.equals( visibility ) )
			return true;
		return false;
	}