If restored or started hidden in systray, report start done to WM directly

src/application.cpp

@@ -209,7 +209,10 @@ QT_WARNING_POP
     if (restoreMode == WindowRestore)
         mainWindow->restore();
     else if (Preferences::self()->showTrayIcon() && Preferences::self()->hideToTrayOnStartup())
+    {
         mainWindow->systemTrayIcon()->hideWindow();
+        KStartupInfo::appStarted();
+    }
     else
         mainWindow->show();
 

src/mainwindow.cpp

@@ -46,6 +46,7 @@
 #include <KStandardShortcut>
 #include <KNotifyConfigWidget>
 #include <KGlobalAccel>
+#include <KStartupInfo>
 
 MainWindow::MainWindow() : KXmlGuiWindow(nullptr)
 {
@@ -672,6 +673,10 @@ bool MainWindow::restore()
 
     // TODO: also save & restore any TrayIcon state, needs API in KStatusNotifierItem
 
+    // in case no window is shown & registered, the window manager needs to be told directly the start is done
+    if (!show)
+        KStartupInfo::appStarted();
+
     return KXmlGuiWindow::restore(1, show);
 }