go to definition fails in c++

This is quite frustrating as it happens quite frequently. I have a variable defined and I hesitate over the type definition and I get a nifty tooltip that shows me the type. But I want to go to the file so I right click and pick "goto defintion". The IDE spins for a bit and then tells me it cannot find the definition.

So how did the tooltip code determine the type. My latest case is:

IShellDispatchPtr pShell;

Put the cursor over "IShellDispatchPtr" and the tooltip says:

typedef _com_ptr_t<_com_IID<IShellDispatch, &__uuidof(IShellDispatch)>> IShellDispatchPtr

But right click on the text and pick goto definition (or declaration) and I get a dialog telling me "A defintion for IShellDispatchPtr could not be located"

So how is the tooltip code so much more powerful in its ability?

R.D. Holland