width = number; 

Specifies the width of a tile. Possible values are an integer or a real number representing the distance in character-width units. Do not specify this value unless the assigned defaults don't provide acceptable appearance. You must specify, however, the width of image tiles and image buttons.

The width of a tile specifies a minimum width. This dimension can be expanded when the tile is laid out unless the width is fixed by one of the fixed_ attributes. Defaults are dynamically assigned based on layout constraints.

Character width units are defined as the average width of all uppercase and lowercase alphabetic characters, or the screen width divided by 80, whichever is less (average width is (width(A .. Z) + width (a .. z)))/52 ).