diff --git a/src/Config.cpp b/src/Config.cpp
index 81491902..7dc2b401 100644
--- a/src/Config.cpp
+++ b/src/Config.cpp
@@ -26,6 +26,8 @@
  */
 
 #include "Config.h"
+#include "DockRegistry_p.h"
+
 #include <QApplication>
 #include <QDebug>
 #include <QOperatingSystemVersion>
@@ -70,8 +72,8 @@ Config::Flags Config::flags() const
 
 void Config::setFlags(Flags f)
 {
-    if (!qApp) {
-        qWarning() << Q_FUNC_INFO << "Only use this function before creating the QApplication";
+    if (!DockRegistry::self()->isEmpty()) {
+        qWarning() << Q_FUNC_INFO << "Only use this function at startup before creating any DockWidget or MainWindow";
         return;
     }
 
diff --git a/src/DockRegistry_p.h b/src/DockRegistry_p.h
index 6dc31c36..95560536 100644
--- a/src/DockRegistry_p.h
+++ b/src/DockRegistry_p.h
@@ -94,10 +94,14 @@ public:
      */
     void ensureAllFloatingWidgetsAreMorphed();
 
+    /**
+     * @brief returns true if there's 0 dockwidgets, 0 main windows
+     */
+    bool isEmpty() const;
+
 private:
     explicit DockRegistry(QObject *parent = nullptr);
     void maybeDelete();
-    bool isEmpty() const;
     DockWidget::List m_dockWidgets;
     MainWindow::List m_mainWindows;
     Frame::List m_frames;