diff --git a/src/root-manager.scm b/src/root-manager.scm
index 475da6e..ab433fa 100644
--- a/src/root-manager.scm
+++ b/src/root-manager.scm
@@ -149,6 +149,20 @@
 	(set-wm-state! dpy window (wm-state withdrawn) none)
 	(if wm
 	    (wm-unmanage-window wm window))))
+     ((client-message-event? xevent)
+      (let* ((p (client-message-event-property xevent))
+	     (type (property:type p))
+	     (data (property:data p))
+	     (window (client-message-event-window xevent))
+	     (wm (manager-of-window root-wm window))
+	     (iconic-state 3))
+	(if (equal? (get-atom-name dpy type) "WM_CHANGE_STATE")
+	    (if (and (eq? (property:format p) (property-format long))
+		     (not (null? data)) (= (car data) iconic-state))
+		(if wm
+		    (wm-iconify-window wm window)
+		    (warn "unmanaged window wants to be iconified"
+			  window))))))
      )))
 
 (define (do-split root-wm orientation new-wm)