diff --git a/src/kernel/desktop-comm.c b/src/kernel/desktop-comm.c
index 62f7d5b2..f760f794 100644
--- a/src/kernel/desktop-comm.c
+++ b/src/kernel/desktop-comm.c
@@ -112,6 +112,7 @@ void mg_TerminateDesktop (void)
 #endif
 
     kernel_free_z_order_info (__mg_zorder_info);
+    __mg_zorder_info = NULL;
     DestroyFreeClipRectList (&sg_FreeClipRectList);
     DestroyFreeClipRectList (&sg_FreeInvRectList);