==23147== 24 bytes in 6 blocks are definitely lost in loss record 3,011 of 6,118
==23147==    at 0x4006AEE: malloc (vg_replace_malloc.c:207)
==23147==    by 0xA88873: g_malloc (gmem.c:131)
==23147==    by 0x3510A6: (within /usr/lib/libgdk-x11-2.0.so.0.1400.0)
==23147==    by 0x35163B: gdk_text_property_to_utf8_list_for_display (in /usr/lib/libgdk-x11-2.0.so.0.1400.0)
==23147==    by 0x328F05: gdk_text_property_to_utf8_list (in /usr/lib/libgdk-x11-2.0.so.0.1400.0)
==23147==    by 0x80AA4B8: meta_text_property_to_utf8 (ui.c:653)
==23147==    by 0x808D811: text_property_from_results (xprops.c:649)
==23147==    by 0x808DE0C: meta_prop_get_values (xprops.c:1137)


The problem here is that gdk_text_property_to_utf8_list always returns an allocated list, even when the returned count is 0. So just change 

  if (count == 0)
    return NULL;

  retval = list[0];
  list[0] = g_strdup (""); /* something to free */

  g_strfreev (list);

to

  if (count == 0)
    retval = NULL
  else
    {
      retval = list[0];
      list[0] = g_strdup (""); /* something to free */
    }

  g_strfreev (list);