diff --git a/activation.cpp b/activation.cpp
--- a/activation.cpp
+++ b/activation.cpp
@@ -254,7 +254,7 @@
 
         // activating a client can cause a non active fullscreen window to loose the ActiveLayer status on > 1 screens
         if (screens()->count() > 1) {
-            for (ClientList::Iterator it = clients.begin(); it != clients.end(); ++it) {
+            for (auto it = m_allClients.begin(); it != m_allClients.end(); ++it) {
                 if (*it != active_client && (*it)->layer() == ActiveLayer && (*it)->screen() == active_client->screen()) {
                     updateClientLayer(*it);
                 }