Window Menu

 New Window On Untitled 

⌥⌘N

Opens a new window viewing the active document. Additional windows will be numbered in the title bar, e.g. myDocument (2).

 Close Window 

⌘W

Closes the currently active window.

 Minimize Window 

⌘M

Minimizes the currently active window to the Dock.

 Zoom Window 

 

Resizes the current window to an optimum size for its contents. If the Option key is held, this command resizes all windows.

 Bring All to Front 

 

Moves all OmniGraffle windows in front of the windows of other active applications.