Index: /trunk/src/VBox/Devices/Input/DevPS2.cpp
===================================================================
--- /trunk/src/VBox/Devices/Input/DevPS2.cpp	(revision 23689)
+++ /trunk/src/VBox/Devices/Input/DevPS2.cpp	(revision 23690)
@@ -678,11 +678,9 @@
     s->mouse_dz += dz;
     s->mouse_dw += dw;
-    /* The issue described above does not affect VBox, and under some
-     * circumstances (which?) we may even wish to send null events to make
-     * mouse integration work. */
     /* In horizontal reporting mode, we may need to send an additional packet
      * for the forth and fifth buttons, as they can't share a packet with a
      * horizontal scroll delta. */
-    if ((s->mouse_buttons & 0x18) != (buttons_state & 0x18))
+    if (   s->mouse_type == 4
+        && (s->mouse_buttons & 0x18) != (buttons_state & 0x18))
         s->mouse_flags |= MOUSE_OUTSTANDING_CLICK;
     s->mouse_buttons = buttons_state;