+    else if (gdk_event->button == 8)
+    {
+        switch (gdk_event->type)
+        {
+            case GDK_3BUTTON_PRESS:
+            case GDK_BUTTON_PRESS:
+                event_type = wxEVT_AUX1_DOWN;
+                break;
+
+            case GDK_2BUTTON_PRESS:
+                event_type = wxEVT_AUX1_DCLICK;
+                break;
+
+            default:
+                ;
+        }
+    }
+
+    else if (gdk_event->button == 9)
+    {
+        switch (gdk_event->type)
+        {
+            case GDK_3BUTTON_PRESS:
+            case GDK_BUTTON_PRESS:
+                event_type = wxEVT_AUX2_DOWN;
+                break;
+
+            case GDK_2BUTTON_PRESS:
+                event_type = wxEVT_AUX2_DCLICK;
+                break;
+
+            default:
+                ;
+        }
+    }
+