diff --git a/build/maus_app.py b/build/maus_app.py
index 05a3eec..246e899 100644
--- a/build/maus_app.py
+++ b/build/maus_app.py
@@ -16,7 +16,7 @@ home = tempfile.mkdtemp()
 os.environ["PROVTOOL_HOME"] = home
 with open(os.path.join(home, "einstellungen.json"), "w") as f:
     json.dump({"assistent_erledigt": True, "tipps_beim_start": False, "fenster": "900x560+100+100",
-               "design": "win95"}, f)  # nur Win95 hat den eigenen Fensterrahmen
+               "design": "win95", "vollbild": False}, f)  # nur Win95 hat den eigenen Fensterrahmen
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 from provtool.gui import app as A  # noqa: E402