1#!/usr/bin/env ruby
2require 'tk'
3
4TkLabel.new(:text=>"Please click the bottom frame").pack
5
6f = TkFrame.new(:width=>400, :height=>100, :background=>'yellow',
7                :relief=>'ridge', :borderwidth=>5).pack
8
9# TkPack.propagate(f, false) # <== important!!
10f.pack_propagate(false)      # <== important!!
11
12list = (1..3).collect{|n|
13  TkButton.new(f, :text=>"button#{'-X'*n}"){
14    command proc{
15      puts "button#{'-X'*n}"
16      self.unpack
17    }
18  }
19}
20
21list.unshift(nil)
22
23f.bind('1', proc{
24         w = list.shift
25         w.unpack if w
26         list.push(w)
27         list[0].pack(:expand=>true, :anchor=>:center) if list[0]
28       })
29
30Tk.mainloop
31