diff --git a/src/plugins/platforms/wayland/plugins/shellintegration/xdg-shell/qwaylandxdgshell.cpp b/src/plugins/platforms/wayland/plugins/shellintegration/xdg-shell/qwaylandxdgshell.cpp
index 5fd718e697b..8cdd0a681bd 100644
--- a/src/plugins/platforms/wayland/plugins/shellintegration/xdg-shell/qwaylandxdgshell.cpp
+++ b/src/plugins/platforms/wayland/plugins/shellintegration/xdg-shell/qwaylandxdgshell.cpp
@@ -36,13 +36,14 @@ QWaylandXdgSurface::Toplevel::Toplevel(QWaylandXdgSurface *xdgSurface)
     requestWindowFlags(window->flags());
     if (auto transientParent = xdgSurface->window()->transientParent()) {
         auto parentSurface = qobject_cast<QWaylandXdgSurface *>(transientParent->shellSurface());
-        if (parentSurface && parentSurface->m_toplevel) {
+        if (parentSurface && parentSurface->m_toplevel)
             set_parent(parentSurface->m_toplevel->object());
-            if (window->modality() != Qt::NonModal && m_xdgSurface->m_shell->m_xdgDialogWm) {
-                m_xdgDialog.reset(m_xdgSurface->m_shell->m_xdgDialogWm->getDialog(object()));
-                m_xdgDialog->set_modal();
-            }
-        }
+    }
+
+    // Always use XDG Dialog, a window could be assigned a parent through XDG Foreign.
+    if (window->modality() != Qt::NonModal && m_xdgSurface->m_shell->m_xdgDialogWm) {
+        m_xdgDialog.reset(m_xdgSurface->m_shell->m_xdgDialogWm->getDialog(object()));
+        m_xdgDialog->set_modal();
     }
 }
 
diff --git a/tests/auto/wayland/xdgshell/tst_xdgshell.cpp b/tests/auto/wayland/xdgshell/tst_xdgshell.cpp
index 311c408a9e5..45b78ed003f 100644
--- a/tests/auto/wayland/xdgshell/tst_xdgshell.cpp
+++ b/tests/auto/wayland/xdgshell/tst_xdgshell.cpp
@@ -35,6 +35,7 @@ private slots:
     void suspended();
     void initiallySuspended();
     void modality();
+    void modalityWithoutTransientParent();
 };
 
 void tst_xdgshell::init()
@@ -823,5 +824,35 @@ void tst_xdgshell::modality()
     QCOMPOSITOR_TRY_VERIFY(!xdgDialog());
 }
 
+void tst_xdgshell::modalityWithoutTransientParent()
+{
+    QRasterWindow child;
+    child.resize(400, 320);
+    child.show();
+    QCOMPOSITOR_TRY_VERIFY(xdgToplevel());
+    QCOMPOSITOR_VERIFY(!xdgDialog());
+
+    child.hide();
+    child.setModality(Qt::WindowModal);
+    child.show();
+    QCOMPOSITOR_TRY_VERIFY(xdgDialog());
+    QCOMPOSITOR_VERIFY(xdgDialog()->modal);
+
+    child.hide();
+    QCOMPOSITOR_TRY_VERIFY(!xdgDialog());
+
+    child.setModality(Qt::ApplicationModal);
+    child.show();
+    QCOMPOSITOR_TRY_VERIFY(xdgDialog());
+    QCOMPOSITOR_VERIFY(xdgDialog()->modal);
+
+    child.hide();
+    QCOMPOSITOR_TRY_VERIFY(!xdgDialog());
+
+    child.show();
+    child.setModality(Qt::NonModal);
+    QCOMPOSITOR_TRY_VERIFY(!xdgDialog());
+}
+
 QCOMPOSITOR_TEST_MAIN(tst_xdgshell)
 #include "tst_xdgshell.moc"