diff --git a/src/server/plasmawindowmanagement_interface.cpp b/src/server/plasmawindowmanagement_interface.cpp
--- a/src/server/plasmawindowmanagement_interface.cpp
+++ b/src/server/plasmawindowmanagement_interface.cpp
@@ -331,6 +331,9 @@
     if (!m_appId.isEmpty()) {
         org_kde_plasma_window_send_app_id_changed(resource, m_appId.toUtf8().constData());
     }
+    if (m_pid != 0) {
+        org_kde_plasma_window_send_pid_changed(resource, m_pid);
+    }
     if (!m_title.isEmpty()) {
         org_kde_plasma_window_send_title_changed(resource, m_title.toUtf8().constData());
     }