The 窶彁oom窶 button is used to expand the active window such that it fills the screen. If you hold down the Option key while clicking the 窶彁oom窶 button, the window will shrink back to its former position. Usually you would use the zoom box on the right hand side of the window title field to control the window size. However, in cases where a window is expanded or moved to a position where this box is outside of the screen or hidden behind the toolbar, you may find the 窶彁oom窶 button useful.
The 窶彁oom窶 button is present in all toolbars except the 窶廩elp toolbar窶 and the 窶廸o document toolbar窶.
