OptionalalignmentThe content alignment of the panel.
Possible values are documented in BoxLayout.Alignment.
The default is 'start'.
OptionaldirectionThe layout direction of the panel.
Possible values are documented in BoxLayout.Direction.
The default is 'top-to-bottom'.
OptionallayoutThe box layout to use for the box panel.
If this is provided, the other options are ignored.
The default is a new BoxLayout.
OptionalspacingThe spacing between items in the panel.
The default is 4.
An options object for initializing a box panel.