Re: Can't place button to needed position.

Try to change:

wmyPanel.orientation = 'column'; // ?.orientation = "stack";

to

myPanel.orientation = 'stack'; // ?

At least the code below gives such UI:

var w = new Window ("dialog", "UI", undefined, );

w.orientation = "stack";
var tpanel = w.add ("tabbedpanel");
tpanel.alignChildren = ["fill", "fill"];
tpanel.preferredSize = [300,300];
var base = tpanel.add ("tab", undefined, "Base");
var work= tpanel.add ("tab", undefined, "Work");
var use = tpanel.add ("tab", undefined, "Use");
var buttonAbout = w.add('button', [0, 0, 20, 20], '?');
buttonAbout.alignment = ['right', 'top'];
w.show ();