--- a/src/kfoldersync.cxx	2017-01-24 10:27:17.000000000 +0100
+++ b/src/kfoldersync.cxx	2021-05-08 23:52:28.891166974 +0200
@@ -173,7 +173,7 @@
 {
     // Connect to dbus (keep it without parent to avoid potential SIGABRT)
     static const KDBusService dbus_service(KDBusService::Unique);
-    connect(&dbus_service, &KDBusService::activateRequested, this, [&]{KStartupInfo::setNewStartupId(this, KStartupInfo::startupId()); KWindowSystem::forceActiveWindow(winId());}, Qt::DirectConnection);
+    connect(&dbus_service, &KDBusService::activateRequested, this, [&]{KStartupInfo::setNewStartupId(this->window()->windowHandle(), KStartupInfo::startupId()); KWindowSystem::forceActiveWindow(winId());}, Qt::DirectConnection);
 
     // Setup toolbar
     QMenu * const app_menu = new QMenu(this);