diff -Nurw gcin-2.3.0.orig/win-gtab.cpp gcin-2.3.0/win-gtab.cpp
--- gcin-2.3.0.orig/win-gtab.cpp	2011-10-27 22:17:35.000000000 +0800
+++ gcin-2.3.0/win-gtab.cpp	2011-12-01 23:18:32.067077963 +0800
@@ -463,6 +463,7 @@
   gtk_orientable_set_orientation(GTK_ORIENTABLE(vbox_top), GTK_ORIENTATION_VERTICAL);
 
   GtkWidget *event_box_gtab = gtk_event_box_new();
+  gtk_event_box_set_visible_window (event_box_gtab, FALSE);
   gtk_container_set_border_width (GTK_CONTAINER (event_box_gtab), 0);
 
   if (gcin_inner_frame) {