From: Mark Volkmann <volkmann2@...>
Date: 2004-11-15T03:05:54+09:00
Subject: update delay related to TkOptionMenu

In the simple code below, when I select something from the 
TkOptionMenubutton, it should cause the value in the TkEntry to be modified 
through the TkVariable named entry_var. However, the change isn't visible 
until I click the TkOptionMenubutton a second time. What am I missing? Is 
there a better way to listen for a selection to be made from the 
TkOptionMenubutton?

Thanks!

---

require 'tk'

root = TkRoot.new
entry_var = TkVariable.new(0)
option_var = TkVariable.new('other')

w = TkOptionMenubutton.new(root, option_var)
w.add('Marathon')
w.add('10K')
w.add('other')
w.pack

w.menu.bind('<MenuSelect>') do
  entry_var.value =
    if option_var.value == 'Marathon' then '26.2'
    elsif option_var.value == '10K' then '6.2'
    else '0'
    end
end

TkEntry.new(root) do
  pack
  textvariable entry_var
end

Tk.mainloop