Index: events.c
===================================================================
--- events.c	(revision 29907)
+++ events.c	(working copy)
@@ -647,6 +647,30 @@
         }
         clientResize (c, part, (XEvent *) ev);
     }
+    else if (ev->button == Button4)
+    {
+        /* Mouse wheel scroll up */
+        if (state == AltMask)
+        {
+            clientIncOpacity(c);
+        }
+        else if (!FLAG_TEST (c->flags, CLIENT_FLAG_SHADED))
+        {
+            clientShade (c);
+        }
+    }
+    else if (ev->button == Button5)
+    {
+        /* Mouse wheel scroll down */
+        if (state == AltMask)
+        {
+            clientDecOpacity(c);
+        }
+        else if (FLAG_TEST (c->flags, CLIENT_FLAG_SHADED))
+        {
+            clientUnshade (c);
+        }
+    }
 }
 
 static int