Missing some properties and methods (Interfaces)

Hi,

I continued to build an application with XULrunner and python, but its a 
bumpy ride.
Some XUL elements are missing special properties and methods.

Interfaces:
Yea, queryInterface helps for some but look up the XUL reference:
Some properties and methods are not defined in the interface for the 
element. And that are the p&ms missing in pyxpcom.

Some examples:
menulist 
<http://www.xulplanet.com/references/elemref/ref_menulist.html>:  
nsIDOMXULSelectControlElement 
<http://www.xulplanet.com/references/xpcomref/ifaces/nsIDOMXULSelectControlElement.html> 
: removeAllItems, disableAutoselect, menuBoxObject,...
iframe: <http://www.xulplanet.com/references/elemref/ref_iframe.html> no 
listed interface
deck <http://www.xulplanet.com/references/elemref/ref_deck.html> : no 
listed interface, but has only properties that are accessible with 
set/getAttribute

Even something easy as "label" needs a queryInterface to address its value.

How does JS address functions that are not part of an interface?
How are these functions implemented?

Bye,
Torsten

p.s.: Should a message to this maillist be in plaintext? The mail 
display on the homepage looked a litte awkward for html mails. :(

Workaround code examples:

deck_dom_ref.selectedIndex:
   deck_dom_ref.getAttribute('selectedIndex')

menulist_dom_ref.removeAllItems():
   while menulist_dom_ref.firstChild.firstChild:
       
menulist_dom_ref.firstChild.removeChild(menulist_dom_ref.firstChild.firstChild)

label_dom_ref.value:
   
label_dom_ref.queryInterface(components.interfaces.nsIDOMXULLabelElement).value