Is Ctrl+F4 (as opposed to Ctrl+W) obsolete for closing a dialog

I wondered about that today when I tried to close a tab in Visual Studio 2015 with Ctrl+W only to discover it doesn't work. Remembering old MFC MDI apps have Ctrl+F4, I tried with that and it worked.

But this made me think - it seems that Ctrl+F4 used to be more prevalent and was associated with Microsoft applications, similar to Ctrl+Y vs Ctrl+Shift+Z for Redo.

On the other hand, Ctrl+W was popularized by web browsers, and it seems most modern apps use that. In fact, I can't remember a non-Microsoft app I've used recently that had Ctrl+F4 but not Ctrl+W for closing a tab.

So this made me think Ctrl+F4 has become effectively obsolete.