The document control menu Next command activates the next document window and moves it to the top of all other documents.
To go to the next document window:
If the document in the Viewer window is not maximized and the title bar is visible, click the icon in the upper left corner of the title bar and select Next
Press ALT+HYPHEN+T
Press CTRL+F6
See Also
Application/Document Control Close
Application/Document Control Maximize
Application/Document Control Minimize
Control Move (Application Window or Viewer Window)