I came across a strange issue that left me pulling my hair out for the past few days.
Here was my problem:
I am using a Telerik PanelBar for navigation, using a sitemap datasource pointing to the SitefinitySiteMap provider. Everything worked great via Visual Studio web server - but when I pushed the application out to a staging server, I noticed that the PanelBar was not automatically expanding on selected items with child items. Here is what I found:
The URL being used on the staging server is: http://(server-name)/ClientName/Homepage/
where "ClientName" is a virtual directory and "Homepage" is an application.
Because I'm lazy, when i type http://(server-name)/clientname/Homepage/
(note: virtual directory is all lowercase) the PanelBar breaks (not auto-expanding). However, when I type http://(server-name)/ClientName/Homepage/
it all works again.
Other things to note:
1) I was able to verify this in VS by forcing it to use a virtual path - case-sensitivity causes the navigation to break.
2) I also noticed that the asp:SiteMapPath control breaks due to case-sensitivity.
3) Haven't tried yet, but my guess is that the same may apply to other navigation controls.