The current default style for button arrangement, which can be reset. The
default setting is GTK_BUTTONBOX_EDGE.
1
GTK_BUTTONBOX_SPREAD
Specifies that the buttons should be spaced evenly across the area of the
buttonbox, with a full-sized space at either edge of the column or row.
2
GTK_BUTTONBOX_EDGE
Specifies that the buttons should be spaced evenly across the area of the
buttonbox, with no space at either edge of the column or row.
3
GTK_BUTTONBOX_START
Specifies that the buttons should be packed from the top or left edge of
the buttonbox, and spaced according to their spacing and internal
padding settings.
4
GTK_BUTTONBOX_END
Specifies that the buttons should be packed from the bottom or right edge
of the buttonbox, and spaced according to their spacing and internal
padding settings.