Hmm, think there might be something odd going on here. As a test, I created a new Visual Studio solution, and added a web project with a WCF service.
If I use my browser (either IE or Chrome) and point them at http://localhost.fiddler:9885/PetsService.svc, the default page loads as expected. If I use the WCF test client, it loads and I can make the service calls.
However, despite adding ".fiddler" to the URL, Fiddler does not show the calls. It shows three entries when I add the service to the WCF test client, but two of them are in red, see the attached screenshot. However, when I make the service calls, nothing more appears in Fiddler.
I don't have any filtering applied.
Anyone any ideas?