A variant of an example in https://creativepro.com/files/kahrel/indesign/scriptui.html, p. 106:
var w = new Window ('dialog', 'Resize', undefined, {resizeable: true});
w.orientation = 'row';
w.box = w.add ('listbox', undefined, ['a', 'b', 'c', 'd'])
w.box.alignment = ['fill', 'fill'];
w.box.minimumSize = [200, 100];
w.buttons = w.add ('group {orientation: "column"}');
w.buttons.alignment = ['right', 'top'];
w.buttons.alignChildren = 'fill';
w.buttons.add ('button {text: "This"}');
w.buttons.add ('button {text: "That"}');
w.buttons.add ('button {text: "And the other"}');
// onResize needed on Mac OS X
w.onResizing = w.onResize = function () {
this.layout.resize ();
}
w.onShow = function () {
w.minimumSize = w.size;
}
w.show ();