VS.NET Solution Explorer Drag & Drop for C++ projects does not work


I am trying to implement 'Drag&Drop' functionality from solution explorer in VS.NET 2005 onto my C# winform.
I have 2 projects within same solution (one C# project, and other MFC C++ project). I have implemented the following events & properties in my C# winform.
My winform contains just one textbox.
  1. DragEnter - for textbox
  2. DragOver - for textbox
  3. AllowDrop property - for textbox
    Also tried with different 'DragDropEffects' enumeration values.
    When I 'Drag&Drop' C# file to my winform, I am able to retrieve the dragged project file path, but the same does not work with C++/Header files and even with project file (csproj, vcproj, etc). While dragging C++/Header file, the mouse cursor shows 'None' (a circle with a line through it), but works fine with C# file.
    Can anyone please help me? I have attached the sample C# winform project.
    Thanks in advance,
    Ahmed Kabir

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