ButtonExpandable

ButtonExpandable is an option for ButtonBox which specifies whether the button should expand to fill any GridBox position in which it appears.

The default setting is ButtonExpandable->True.

This setting is usually used for all buttons that appear in palettes.

With ButtonExpandable->False the size of a button is determined purely by its contents, independent of its environment.

With ButtonExpandable->False, gutters will often be left between buttons in a GridBox.

See The Mathematica Book: Section 2.8.11.

See also: ButtonMargins, ButtonMinHeight, TextJustification.