Revert "Move FloatingWindow::setupWindow() into a reusable function"

This reverts commit 6fea5af585.
Need to fix the windows build first

src/private/FloatingWindow.cpp

@@ -102,7 +102,7 @@ FloatingWindow::FloatingWindow(MainWindowBase *parent)
 {
     if (kddwUsesQtWidgets()) {
         // For QtQuick we do it a bit later, once we have the QQuickWindow
-        WidgetResizeHandler::setupWindow(windowHandle());
+        setupWindow();
     }
 
     DockRegistry::self()->registerFloatingWindow(this);
@@ -145,6 +145,35 @@ FloatingWindow::~FloatingWindow()
     DockRegistry::self()->unregisterFloatingWindow(this);
 }
 
+void FloatingWindow::setupWindow()
+{
+    // Does some minor setup on our QWindow.
+    // Like adding the drop shadow on Windows and two other workarounds.
+
+#if defined(Q_OS_WIN)
+    // On Windows with Qt 5.9 (and maybe earlier), the WM_NCALCSIZE isn't being processed unless we explicitly create the window.
+    // So create it now, otherwise floating dock widgets will show a native title bar until resized.
+    create();
+
+    if (KDDockWidgets::usesAeroSnapWithCustomDecos()) {
+# ifdef KDDOCKWIDGETS_QTWIDGETS
+        m_nchittestFilter = new NCHITTESTEventFilter(this);
+        qApp->installNativeEventFilter(m_nchittestFilter);
+#endif
+        connect(windowHandle(), &QWindow::screenChanged, this, [this] {
+            // Qt honors our frame hijacking usually... but when screen changes we must give it a nudge.
+            // Otherwise what Qt thinks is the client area is not what Windows knows it is.
+            // SetWindowPos() will trigger an NCCALCSIZE message, which Qt will intercept and take note of the margins we're using.
+            SetWindowPos(HWND(winId()), 0, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE | SWP_NOZORDER | SWP_FRAMECHANGED);
+        });
+
+        // Show drop-shadow:
+        MARGINS margins = {0, 0, 0, 1}; // arbitrary, just needs to be > 0 it seems
+        DwmExtendFrameIntoClientArea(HWND(winId()), &margins);
+    }
+#endif // Q_OS_WIN
+}
+
 #if defined(Q_OS_WIN) && defined(KDDOCKWIDGETS_QTWIDGETS)
 bool FloatingWindow::nativeEvent(const QByteArray &eventType, void *message, Qt5Qt6Compat::qintptr *result)
 {

src/private/FloatingWindow_p.h

@@ -168,6 +168,7 @@ Q_SIGNALS:
     void numFramesChanged();
     void windowStateChanged(QWindowStateChangeEvent *);
 protected:
+    void setupWindow();
     void maybeCreateResizeHandler();
 
 #if defined(Q_OS_WIN) && defined(KDDOCKWIDGETS_QTWIDGETS)

src/private/WidgetResizeHandler.cpp

@@ -488,37 +488,6 @@ CursorPosition WidgetResizeHandler::cursorPosition(QPoint globalPos) const
     return static_cast<CursorPosition>(result);
 }
 
-/** static */
-void WidgetResizeHandler::setupWindow(QWindow *window)
-{
-    // Does some minor setup on our QWindow.
-    // Like adding the drop shadow on Windows and two other workarounds.
-
-#if defined(Q_OS_WIN)
-    if (KDDockWidgets::usesAeroSnapWithCustomDecos()) {
-#ifdef KDDOCKWIDGETS_QTWIDGETS
-        m_nchittestFilter = new NCHITTESTEventFilter(this);
-        qApp->installNativeEventFilter(m_nchittestFilter);
-#endif
-        const auto wid = HWND(window->winId());
-        connect(window, &QWindow::screenChanged, this, [this] {
-            // Qt honors our frame hijacking usually... but when screen changes we must give it a
-            // nudge. Otherwise what Qt thinks is the client area is not what Windows knows it is.
-            // SetWindowPos() will trigger an NCCALCSIZE message, which Qt will intercept and take
-            // note of the margins we're using.
-            SetWindowPos(wid, 0, 0, 0, 0, 0,
-                         SWP_NOMOVE | SWP_NOSIZE | SWP_NOZORDER | SWP_FRAMECHANGED);
-        });
-
-        // Show drop-shadow:
-        MARGINS margins = { 0, 0, 0, 1 }; // arbitrary, just needs to be > 0 it seems
-        DwmExtendFrameIntoClientArea(wid, &margins);
-    }
-#else
-    Q_UNUSED(window);
-#endif // Q_OS_WIN
-}
-
 #if defined(Q_OS_WIN) && defined(KDDOCKWIDGETS_QTWIDGETS)
 bool NCHITTESTEventFilter::nativeEventFilter(const QByteArray &eventType, void *message,
                                              Qt5Qt6Compat::qintptr *result)

src/private/WidgetResizeHandler_p.h

@@ -69,8 +69,6 @@ public:
 
     static int widgetResizeHandlerMargin();
 
-    static void setupWindow(QWindow *window);
-
 #ifdef Q_OS_WIN
     static bool handleWindowsNativeEvent(FloatingWindow *w, const QByteArray &eventType, void *message, Qt5Qt6Compat::qintptr *result);
 #endif

src/private/quick/FloatingWindowQuick.cpp

@@ -187,7 +187,7 @@ void FloatingWindowQuick::init()
     }
 
     QWidgetAdapter::setParent(m_quickWindow->contentItem());
-    WidgetResizeHandler::setupWindow(m_quickWindow);
+    setupWindow();
     m_quickWindow->installEventFilter(this); // for window resizing
     maybeCreateResizeHandler();
 

src/private/quick/FrameQuick.cpp

@@ -21,7 +21,7 @@
 #include "Config.h"
 #include "FrameworkWidgetFactory.h"
 #include "TabWidgetQuick_p.h"
-#include "WidgetResizeHandler_p.h"
+
 #include <QDebug>
 
 using namespace KDDockWidgets;