diff --git a/src/gtk/timer.cpp b/src/gtk/timer.cpp
index a8514f8cd1..721b0f6c0b 100644
--- a/src/gtk/timer.cpp
+++ b/src/gtk/timer.cpp
@@ -30,9 +30,17 @@ extern "C" gint timeout_callback( gpointer data )
 {
     wxTimer *timer = (wxTimer*)data;
 
-    /* when getting called from GDK's timer handler we
-       are no longer within GDK's grab on the GUI
-       thread so we must lock it here ourselves */
+    // Don't change the order of anything in this callback!
+    
+    if ( timer->IsOneShot() )
+    {
+        // This sets m_tag to -1
+        timer->Stop();
+    }
+
+    // when getting called from GDK's timer handler we
+    // are no longer within GDK's grab on the GUI
+    // thread so we must lock it here ourselves
     gdk_threads_enter();
 
     timer->Notify();
@@ -40,7 +48,7 @@ extern "C" gint timeout_callback( gpointer data )
     /* release lock again */
     gdk_threads_leave();
 
-    if ( timer->IsOneShot() )
+    if (timer->IsOneShot())
         return FALSE;
 
     return TRUE;
diff --git a/src/gtk1/timer.cpp b/src/gtk1/timer.cpp
index a8514f8cd1..721b0f6c0b 100644
--- a/src/gtk1/timer.cpp
+++ b/src/gtk1/timer.cpp
@@ -30,9 +30,17 @@ extern "C" gint timeout_callback( gpointer data )
 {
     wxTimer *timer = (wxTimer*)data;
 
-    /* when getting called from GDK's timer handler we
-       are no longer within GDK's grab on the GUI
-       thread so we must lock it here ourselves */
+    // Don't change the order of anything in this callback!
+    
+    if ( timer->IsOneShot() )
+    {
+        // This sets m_tag to -1
+        timer->Stop();
+    }
+
+    // when getting called from GDK's timer handler we
+    // are no longer within GDK's grab on the GUI
+    // thread so we must lock it here ourselves
     gdk_threads_enter();
 
     timer->Notify();
@@ -40,7 +48,7 @@ extern "C" gint timeout_callback( gpointer data )
     /* release lock again */
     gdk_threads_leave();
 
-    if ( timer->IsOneShot() )
+    if (timer->IsOneShot())
         return FALSE;
 
     return TRUE;