diff --git a/src/plugins/platforms/xcb/qxcbwindow.cpp b/src/plugins/platforms/xcb/qxcbwindow.cpp
index 007837ebf5e..7fd6fc0c4e3 100644
--- a/src/plugins/platforms/xcb/qxcbwindow.cpp
+++ b/src/plugins/platforms/xcb/qxcbwindow.cpp
@@ -1325,6 +1325,7 @@ void QXcbWindow::setParent(const QPlatformWindow *parent)
         m_embedded = false;
     }
     xcb_reparent_window(xcb_connection(), xcb_window(), xcb_parent_id, topLeft.x(), topLeft.y());
+    connection()->sync();
 }
 
 void QXcbWindow::setWindowTitle(const QString &title)