I've added the code below to detect "alt" keyboard event > set the menuBar visible [mousepad-window.h](/uploads/927bb85e92f85000d5c6136dde91fe97/mousepad-window.h) Because i was unable to compile without this few lines > #ifndef G_SOURCE_FUNC #define G_SOURCE_FUNC(f) ((GSourceFunc) (void (*)(void)) (f)) #endif [mousepad-window.c](/uploads/7937d950c810fe37cbfde0a3495ac7b2/mousepad-window.c) > static gboolean set_menubar_visible_keyboard_shortcut (MousepadWindow *window, GdkEventKey *event, gpointer data) { if (event->keyval == GDK_KEY_Alt_L || event->keyval == GDK_KEY_Alt_R){ gtk_widget_set_visible (window->menubar, TRUE); return TRUE; } return FALSE; } And inside the **mousepad_window_create_menubar**'s function >// Detect keyboard "Alt" Shortcut gtk_widget_add_events(window, GDK_KEY_PRESS_MASK); g_signal_connect (G_OBJECT (window), "key_press_event", G_CALLBACK (set_menubar_visible_keyboard_shortcut), NULL);