VS can not find header file(compiler can)

Maybe stupid question:
I want to do some socket programming in UE4.9. When I include “Sockets.h” and “Networking.h”, after add module in dependency, compiler does well but VS cannot find it. I know it’s not a big issue, but these auto completion doesn’t work at this time.
Anyone know how to solve it?

Thanks.

Update: having a full path include definitely works for VS.
#include “Runtime\Sockets\Public\Sockets.h” instead of
#include “Sockets.h”
But that’s also annoying.