Screenshots demonstrate the problem. When I search for "NetImpl", I see a result, "Dlc::NetImpl". However, when I search for "Dlc::NetImpl", there are no matches.
The problem doesn't seem to be related to the namespace separator, since other queries that include "::" work.
I am running version 17.0.0.1 on Win32, but I don't know if this behavior exists in stable version 16.