diff --git i/linux/my_application.cc w/linux/my_application.cc
index 2996a7e..64caadc 100644
--- i/linux/my_application.cc
+++ w/linux/my_application.cc
@@ -20,12 +20,7 @@ static void my_application_activate(GApplication* application) {
   GtkWindow* window =
       GTK_WINDOW(gtk_application_window_new(GTK_APPLICATION(application)));
 
-  GtkHeaderBar* header_bar = GTK_HEADER_BAR(gtk_header_bar_new());
-  gtk_widget_show(GTK_WIDGET(header_bar));
-  gtk_header_bar_set_title(header_bar, "goguma");
-  gtk_header_bar_set_show_close_button(header_bar, TRUE);
-  gtk_window_set_titlebar(window, GTK_WIDGET(header_bar));
-
+  gtk_window_set_decorated(window, FALSE);
   gtk_window_set_default_size(window, 1280, 720);
   gtk_widget_show(GTK_WIDGET(window));