diff --git a/client.c b/client.c
index 917b1013..89a56fe1 100644
--- a/client.c
+++ b/client.c
@@ -509,7 +509,7 @@ client_manage(xcb_window_t w, xcb_get_geometry_reply_t *wgeom, int phys_screen,
     /* update window title */
     property_update_wm_name(c);
     property_update_wm_icon_name(c);
-    property_update_wm_class(c);
+    property_update_wm_class(c, NULL);
 
     xutil_text_prop_get(globalconf.connection, c->win, _NET_STARTUP_ID, &c->startup_id, NULL);
 
diff --git a/property.c b/property.c
index dd4e00b4..79565e8a 100644
--- a/property.c
+++ b/property.c
@@ -221,22 +221,34 @@ property_update_wm_name(client_t *c)
     hooks_property(c, "name");
 }
 
+/** Update WM_CLASS of a client.
+ * \param c The client.
+ * \param reply The reply to get property request, or NULL if none.
+ */
 void
-property_update_wm_class(client_t *c)
+property_update_wm_class(client_t *c, xcb_get_property_reply_t *reply)
 {
     xcb_get_wm_class_reply_t hint;
 
+    if(reply)
+    {
+        if(!xcb_get_wm_class_from_reply(&hint, reply))
+            return;
+    }
+    else
+    {
+        if(!xcb_get_wm_class_reply(globalconf.connection,
+                                   xcb_get_wm_class_unchecked(globalconf.connection, c->win),
+                                   &hint, NULL))
+            return;
+    }
+
     p_delete(&c->instance);
     p_delete(&c->class);
 
-    if(xcb_get_wm_class_reply(globalconf.connection,
-                               xcb_get_wm_class_unchecked(globalconf.connection, c->win),
-                               &hint, NULL))
-    {
-        c->instance = a_strdup(hint.instance_name);
-        c->class = a_strdup(hint.class_name);
-        xcb_get_wm_class_reply_wipe(&hint);
-    }
+    c->instance = a_strdup(hint.instance_name);
+    c->class = a_strdup(hint.class_name);
+    xcb_get_wm_class_reply_wipe(&hint);
 }
 
 /** Update client icon name attribute with its new title.
@@ -304,7 +316,7 @@ property_handle_wm_class(void *data,
     client_t *c = client_getbywin(window);
 
     if(c)
-        property_update_wm_class(c);
+        property_update_wm_class(c, reply);
 
     return 0;
 }
diff --git a/property.h b/property.h
index 1c98fe0c..259821f2 100644
--- a/property.h
+++ b/property.h
@@ -25,10 +25,10 @@
 #include "structs.h"
 
 void property_update_wm_transient_for(client_t *, xcb_get_property_reply_t *);
-void property_update_wm_client_leader(client_t *c, xcb_get_property_reply_t *reply);
+void property_update_wm_client_leader(client_t *c, xcb_get_property_reply_t *);
 void property_update_wm_normal_hints(client_t *, xcb_get_property_reply_t *);
 void property_update_wm_hints(client_t *, xcb_get_property_reply_t *);
-void property_update_wm_class(client_t *);
+void property_update_wm_class(client_t *, xcb_get_property_reply_t *);
 void property_update_wm_name(client_t *);
 void property_update_wm_icon_name(client_t *);
 void a_xcb_set_property_handlers(void);