--- a/src/theme/qxdgdesktopportalfiledialog.cpp~	2022-01-11 10:46:15.000000000 +0100
+++ b/src/theme/qxdgdesktopportalfiledialog.cpp	2022-04-26 12:16:07.504955234 +0200
@@ -165,7 +165,7 @@
                                                           QLatin1String("/org/freedesktop/portal/desktop"),
                                                           QLatin1String("org.freedesktop.portal.FileChooser"),
                                                           d->saveFile ? QLatin1String("SaveFile") : QLatin1String("OpenFile"));
-    QString parentWindowId = QLatin1String("x11:") + QString::number(d->winId);
+    QString parentWindowId = QLatin1String("x11:") + QString::number(d->winId, 16);
 
     QVariantMap options;
     if (!d->acceptLabel.isEmpty())