A layout can be just None, if it takes no options, or a dict of options specifying how to arrange the element. The layout mechanism uses a simplified version of the pack geometry manager: given an initial cavity, each element is allocated a parcel. Valid options/values are:

    • side: whichsideSpecifies which side of the cavity to place the element; one of top, right, bottom or left. If omitted, the element occupies the entire cavity.
    • sticky: nsweSpecifies where the element is placed inside its allocated parcel.
    • unit: 0 or 1If set to 1, causes the element and all of its descendants to be treated as a single element for the purposes of Widget.identify() et al. It’s used for things like scrollbar thumbs with grips.
    • children: [sublayout… ]Specifies a list of elements to place inside the element. Each element is a tuple (or other sequence type) where the first item is the layout name, and the other is a Layout.