Repro steps

Make sure you have a second app running, like a browser that can be tabbed into
Make sure the text editor is open and focused, type "class Foo"
Press Command-Tab to switch focus from the IDE to the browser
Press Command-Tab to switch back to the IDE
Attempt to type: you will notice that the editor is no longer focused, and the input goes somewhere else.

Scenario

This happens a lot when I am porting code, and I have to switch from VSMac to other tools (Safari, Emacs, Terminal).

I provided an attachment (large) for internal use on an older version of this bug (as I think I did not file it properly):

VS bug #754535