Good or evil - SetParent() win32 API between different processes

The SetParent function takes a child and new parent window handle. This also seems to work when the child window is in a different Windows process.

I have seen a post that claims this is not officially supported, but the current docs don't mention this any more. Is this a flaw in the current docs, or did this behavior change?

HWND WINAPI SetParent(
  __in      HWND hWndChild,
  __in_opt  HWND hWndNewParent
);