I tried to replicate the problem on my end but didn't succeeded. The problem does seems strange though. Can you please check the following:
2. Click on the Resources Tab and Enable the tracking if needed
3. Check if all resource files are loaded in both cases (with small and capital letter).
I don't thing that this will be an issue when you deploy the web site, since most probably it will be accessed by domain only. If you we can not find the reason, you might want to create a HttpModule which redirects the requests to such having small letters only.
p.s. Nice blog p0sts! :)
the Telerik team