One way to build this sample with Visual Studio is to create a new C++ Win32 project, choose Win32 Console Application, check the checkbox 'Add common header files for MFC', Finish, then paste the code below into the resulting starter source file. I've tried to create a sample program below to demonstrate the problem.

As a result, our client application's HTTP request to the server does not send the cookies back to the server and the Single Sign On software on the server side then sends a Sign On HTML page in the response, rather than the document resource the client application requested. Though we can locate the client window(s) using EnumWindows, just having the client window's HWND doesn't seem to let us get the cookies.

The SHDocVw::ShellWindows collection does not seem to find these 'IE mode' tab windows that are running on Edge. As IE has now been retired as of June 2022, customers are trying to run the application in Edge in IE mode. In IE, the client application is able to 'find' its IE tab by using Microsoft's SHDocVw::ShellWindows collection, and is also able to get the cookies from that tab. For customers using Single Sign On products, like SiteMinder, our client application may need to send back one or more cookies (like SMSESSION) that were initially sent by the server application. It performs document editing, and sometimes needs to make HTTP requests back the server application to get additional resources. The application displays in the IE browser tab, but it runs in its own process, not in the IE browser tab process. One of our Windows client applications, which uses some Microsoft Active Document / ActiveX technology, requires that users use the IE browser.

Ie tab for edge