Conditional problem

Hello!

I have a page with a component in it. The page has a persistent property 'openedFolderId' which I would like to use in the component definition. The component has a property named 'folder'.
If I write in the component definition:

    <component id="ifFolderOpened" type="Conditional">
        <binding name="condition" expression="page.openedFolderId == folder.id"/>
    </component>

then I get an exception:
          
          ognl.NoSuchPropertyException 
          folder 


BUT if I write:

    <component id="ifFolderOpened" type="Conditional">
        <binding name="condition" expression="page.openedFolderId == page.components.categories.folder.id"/>
    </component>

where 'categories' is the name of my component in the page definition then it works!

Help me, what am I doing wrong?
Thanks,
Norbi