the #GtkWidget to be added to @box
%TRUE if the new child is to be given extra space allocated to @box. The extra space will be divided evenly between all children of @box that use this option
%TRUE if space given to @child by the @expand option is actually allocated to @child, rather than just padding it. This parameter has no effect if @expand is set to %FALSE. A child is always allocated the full height of a horizontal #GtkBox and the full width of a vertical #GtkBox. This option affects the other dimension
extra space in pixels to put between this child and its neighbors, over and above the global amount specified by #GtkBox:spacing property. If @child is a widget at one of the reference ends of @box, then @padding pixels are also put between @child and the reference edge of @box
Adds @child to @box, packed with reference to the end of @box. The @child is packed after (away from end of) any other child packed with reference to the end of @box.