diff --git a/libtaskmanager/xwindowtasksmodel.cpp b/libtaskmanager/xwindowtasksmodel.cpp
--- a/libtaskmanager/xwindowtasksmodel.cpp
+++ b/libtaskmanager/xwindowtasksmodel.cpp
@@ -307,20 +307,22 @@
         const KWindowInfo info(window, NET::WMState | NET::XAWMState, NET::WM2TransientFor);
 
         if (info.hasState(NET::DemandsAttention)) {
-            WId oldLeader = info.transientFor();
+            const WId leader = info.transientFor();
+            WId oldLeader = 0;
             QMutableHashIterator<WId, WId> i(transientsDemandingAttention);
 
             while (i.hasNext()) {
                 i.next();
 
                 if (i.value() == window) {
                     oldLeader = i.key();
-                    i.remove();
+
+                    break;
                 }
             }
 
-            if (oldLeader != 0) {
-                const WId leader = info.transientFor();
+            if (oldLeader != 0 && leader != oldLeader) {
+                i.remove();
                 transientsDemandingAttention.insertMulti(leader, window);
                 dataChanged(oldLeader, QVector<int>{IsDemandingAttention});
                 dataChanged(leader, QVector<int>{IsDemandingAttention});