title: GTK - Don't highlight buttons on select / hover
body: <p>I'm trying to write a kiosk GUI in ruby/gtk on ubuntu. I'm pretty fluent in ruby, but new to writing GUIs and not great with linux. </p>
  
  <p>I'm using a touch screen, and am using our own images for buttons, e.g.</p>
  
  <pre><code>button_image = Gtk::Image.new(Gdk::Pixbuff.new "images/button_image.png")
  @button = Gtk::Button.new 
  @button.add(button_image)
  @button.set_relief(Gtk::RELIEF_NONE)
  </code></pre>
  
  <p>My issue is that when the buttons are pressed or remain selected (or hovered over, although this is less relevant with a touch screen), gtk shows fat, square borders around them. Obviously it's applying gtk's prelight / selected / active lighting to the buttons. I've tried changing the button properties in various ways, and also tryied hacking apart my theme, and while I can modify how the highlighting looks, I can't seem to completely get rid of it. Changing the color of the highlight via my theme is easy, but if I remove my setting there's still a default I can't get rid of.</p>
  
  <p>Does anyone know if there's a way to stop it, or possibly make it transparent? Thanks in advance!</p>