desktop-shell: don't crash on menu

Add dummy menu callback function, so we don't crash after every time
someone opens the menu.

Signed-off-by: Pekka Paalanen <ppaalanen@gmail.com>

clients/desktop-shell.c

@@ -131,6 +131,12 @@ sigchild_handler(int s)
 		fprintf(stderr, "child %d exited\n", pid);
 }
 
+static void
+menu_func(struct window *window, int index, void *data)
+{
+	printf("Selected index %d from a panel menu.\n", index);
+}
+
 static void
 show_menu(struct panel *panel, struct input *input, uint32_t time)
 {
@@ -142,7 +148,7 @@ show_menu(struct panel *panel, struct input *input, uint32_t time)
 	input_get_position(input, &x, &y);
 	window_show_menu(window_get_display(panel->window),
 			 input, time, panel->window,
-			 x - 10, y - 10, NULL, entries, 4);
+			 x - 10, y - 10, menu_func, entries, 4);
 }
 
 static void