thanks for your reply.
in fact, the web.config was alreay set as :
and even though, the problem occured.
I did find the problem, though, which is kind of odd.
Initially IIS (5.0 for testing/dev, but also IIS7.0 on Win2k8) was set for authentication mode as "Anonymous", and the problem i mentioned on my 1st post does occur.
If i set security on IIS5.0 to "Integrated Windows authentication" AND "Digest authentication for Windows domain server" to ON
and set "Anonymous Access to OFF"
, the problem does not occur, i can click on each node of the SiteMap's Treeview control that the pages list will update correctly.
The problem also does NOT occur if is switch off "Digest authentication for Windows domain server".
We use impersonate :
could this be a problem? it doesn't make much sense, i guess....