Start adding editor, fix up sidebar styling

src-tauri/src/main.rs

@@ -46,7 +46,7 @@ fn build_menu(app_name: &str) -> Menu {
     }
     let open_folder =
         CustomMenuItem::new("openfolder".to_string(), "Open Folder").accelerator("cmd+shift+O");
-    let file_submenu = Menu::new()
+    let mut file_submenu = Menu::new()
         .add_item(open_folder)
         .add_native_item(MenuItem::CloseWindow);
     #[cfg(not(target_os = "macos"))]