Add a comment about the fix.

Author: xStrom

druid-shell/src/platform/mac/application.rs

@@ -172,6 +172,8 @@ lazy_static! {
 extern "C" fn application_did_finish_launching(_this: &mut Object, _: Sel, _notification: id) {
     unsafe {
         let ns_app = NSApp();
+        // We need to delay setting the activation policy and activating the app
+        // until we have the main menu all set up. Otherwise the menu won't be interactable.
         ns_app.setActivationPolicy_(NSApplicationActivationPolicyRegular);
         let () = msg_send![ns_app, activateIgnoringOtherApps: YES];
     }