Created attachment 130036 [details]
Screenshot

Looks to me like a clearlooks specific thing. I only see it there. I tried the following with no errors:
crux, darkroom, glider, glossy, human, and mist,

This is caused by the following code in gnomine.c:

  /* This is evil, but the normal button focus indicator 
   * interferes with the face (but we still want the button
   * to be the default). */
  gtk_rc_parse_string
    ("style \"gnomine\" { GtkButton::interior-focus = 0 } class \"GtkButton\" style \"gnomine\"");


Removing it has no obvious bad effect with current themes, and makes the redraw problems with Clearlooks go away.

Looks sane to me. I'll commit your fix today.

commit ede2f338ef9a2ac0a32f88561d5db40b28bcaa45
Author: Jason D. Clinton <me@jasonclinton.com>
Date:   Mon Aug 24 11:52:33 2009 -0500

    gnomine: Fix resizing button theme artifact, #574118, Matthias Clasen

diff --git a/gnomine/gnomine.c b/gnomine/gnomine.c
index 37567fe..f773a4f 100644
--- a/gnomine/gnomine.c
+++ b/gnomine/gnomine.c
@@ -1067,12 +1067,6 @@ main (int argc, char *argv[])
 
   verify_ranges ();
 
-  /* This is evil, but the normal button focus indicator 
-   * interferes with the face (but we still want the button
-   * to be the default). */
-  gtk_rc_parse_string
-    ("style \"gnomine\" { GtkButton::interior-focus = 0 } class \"GtkButton\" s
-
   window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
   gtk_window_set_title (GTK_WINDOW (window), _(APP_NAME_LONG));