Cannot select default pages in object browser

[pgrunewald]

When using MultiContentTreeFieldWidget or any other widget that uses the file browser (@@contentree-fetch), it is impossible to select any default page. In my case, I would like the user to select a set of Documents. Some of them being a default page for its folder are unfortunately out of scope for the file browser. For example, when clicking on a folder with a single document being a default page, it does not show this document as one of its child.

The problem seems to be in these lines within widget.py.

if 'is_default_page' not in navtree_query:
    navtree_query['is_default_page'] = False

I tried to circumvent this issue by providing a source, which has its navtree_query populated with [True, False] for 'is_default_page' in hope, that any value would suffice. No need to explain, that it did not worked, otherwise would this issue would not have been written.

What is the relevance of the above mentioned constraint and if none existing, can we remove it?

I'm using Plone 4.3.7 and plone.formwidget.contenttree 1.0.9.