Button release makes button look different, how do I stop this?

[Antony Stace <antony claire co jp>]

Hi Folks

I have created some buttons and change the colour of them with the
following code

[snip]
 color.red   = BUTTON_GREY_RED;
  color.green = BUTTON_GREY_GREEN;
  color.blue  = BUTTON_GREY_BLUE;

  gdk_color_alloc(gdk_colormap_get_system(), &color);
  new_style                =
gtk_style_copy(gtk_widget_get_default_style());
  new_style->bg[GTK_STATE_NORMAL]   = color;
  new_style->bg[GTK_STATE_PRELIGHT] = color;
  new_style->bg[GTK_STATE_ACTIVE]   = color;

  gtk_widget_set_style(GTK_WIDGET(fly1Button), new_style);
  gtk_widget_set_style(GTK_WIDGET(fly2Button), new_style);
  gtk_widget_set_style(GTK_WIDGET(ret1Button), new_style);
  gtk_widget_set_style(GTK_WIDGET(ret2Button), new_style);
  gtk_widget_set_style(GTK_WIDGET(water2Button), new_style);
  gtk_widget_set_style(GTK_WIDGET(water2Button), new_style);
[snip]

When I run the app and release a button after I have pushed it that
particular button(pressed button) looks a little different from the
other buttons(other buttons).  The bottom and right edges are darker on
(pressed button)  than on (other buttons).  How can I make it so when
the button is released (pressed button) looks the same as (other
buttons)

Cheers

Antony