ATL activex MSDN tutorial example: why do I get intellisense errors?

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C++

ATL

ActiveX

I used the MSDN ActiveX Template Library (ATL) Tutorial to build the "Polygon" ActiveX Control. I followed the instructions on the MSDN Tutorial, and everything went well until I added the "PolyCtl" control to the project. After adding the PolyCtl control, it generated PolyCtl.cpp and PolyCtl.h files and it gave 9 IntelliSense errors such as: (1) IntelliSense: identifier "IPolyCtlEvents" is undefined, (2) IntelliSense: identifier "CLSID_PolyCtl" is undefined, (3) IntelliSense: identifier "IPolyCtl" is undefined, (4) IntelliSense: identifier "IID_IPolyCtl" is undefined.... etc. I did not add any extra code. I just followed the MSDN tutorial instructions to create PolyCtl control. Why do I get the IntelliSense errors?

What I have tried:

I thought that I was doing something wrong. So, I downloaded the Sample Code for the "Polygon ATL ActiveX Control" example from MSDN website. When I open the project, that code also gives the same errors. Does anyone know what causes these errors and how to fix it? I cannot build the project because of these errors. Thanks.

Gopal Bhat