furthermore, on any app, don't disable a button when an action isn't available. you can still mark it as disabled via color, but if someone clicks on it, you sh

furthermore, on any app, don't disable a button when an action isn't available. you can still mark it as disabled via color, but if someone clicks on it, you should show them a message WHY that action isn't available. "Sorry, you haven't filled in your phone number", etc.