This proposal is not a bug fix.

In my testing on Windows today, Ryan is correct in saying (on the PR) that kp return key normally acts is same as normal return key.  True regardless of Numlock.  This is *also true*, at least on Windows, of instances of SimpleDialog, Dialog, and _QueryDialog.  I tested _QueryDialog via IDLE's use of askinteger.  I believe the patch has no effect on Windows.

I have the impression that the Windows behavior in not standard on *nix, where tcl/tk was first implemented.  I would not change behavior on *nix with Serhiy's okay, and I would not expect it.

IDLE adds KP_Enter bindings in a couple of its own dialogs with defaults.  I don't remember if I inherited these, but I believe that there was a pre-existing policy of trying to make IDLE acts the same across systems, which I have adopted also.  But a *nix-only tkinter app should not have Windows behavior imposed on it. 

I cannot test on my no-numberpad Macbook Air.