WindowMargins

WindowMargins is an option for notebooks that determines the size of margins around the notebook window.

WindowMargins {{left, right, {bottom, top determines the distances from each edge of your screen to each edge of the window.

The values of left, right, bottom, and top are given in points, where 72 points equal one inch.

Negative values of left, right, bottom, and top represent edges that are off the screen.

Typically only two distances are given explicitly; the others are Automatic, indicating that they should be determined from the size of the window. The settings for WindowMargins change automatically whenever you move a window around interactively using the front end. The window edges closer to the edges of the screen are typically assigned explicit margin distances; the other edges are set to Automatic. This allows the same setting for WindowMargins to work on screens of different sizes.

With WindowSize {Automatic, Automatic} all four margin distances must be given explicitly.

With the default setting WindowMargins Automatic, new windows are placed on your screen in such a way as to make visible as many window title bars as possible.

See The Mathematica Book: Section 2.11.13.

See also: WindowSize, WindowMovable.