MacOS – Does OS X Notification Center receive messages from APNS, LAN or just locally

You could use a 3rd party calendar app just for their notification functions as a bodgy workaround.

I recommend Calvetiva, Agenda, or Tempus.

The workflow would go something like this:

1. Choose a secondary calendar app.
2. Configure you secondary calendar app to only use the calendars you want alerts for (steps vary on choice of app). Some (like Calvetica) are clever, and extend the alerts function by allowing a snooze option etc.
3. Configure secondary calendar alerts and notifications via the normal settings> notifications app to show as you want them. They will only trigger for the active calendars in the app.
4. Configure your normal calendar alerts to be off. Remove from Notification Centre, set alert style to none, and also go onto Sounds > alerts and set the calendar alert to none.

Now your existing calendar app will still have access to all calendars but won't alert, the secondary app will do alerting only for the active ones.

Downsides: You will need to periodically open and then shut the secondary calendar every so often in order for it to read the current alerts from the calendar data store and create it's own local notifications from them.

I hoped you could get round this by following the above steps but using the built in calendar as your selective alerting calendar (as it is always running and won't need to be opened to update), and using a replacement calendar app with all calendars shown but no alerts - sadly the normal Calendar app includes all calendars regardless of if you have turned a calendar off or not.

I'm a Mac OS X developer and I just finished adding Notification Center support to my app. For what it's worth, here's what I found out:

• By default, notifications (the alerts) are NOT shown if the application is already frontmost (this explains why alerts refuse to show up sometimes, and you only see the notification in Notification Center). This is up to given applications to overwrite and it is not very straightforward, so do expect most applications to not show notifications when they're active. In my opinion, this is very annoying.
• The application, after sending a notification still has a lot of control over that given notification. It can remove it from your screen at any time it wants, regardless of the settings you have. Basically, if Safari, for some reason was set to remove notifications after X seconds, it will do that, your settings do not matter.

I have no idea if this is a bug in Safari or Notification Center, or both. However, I am fairly confident that there is nothing you can do about the second issue (there might be a hidden defaults setting for the first one, but I haven't heard of it). I did check the WebKit API Specification, to make sure it's not something that the individual websites are doing, and you can rule out websites from your suspect's list, because they do not have any control over the notifications.

I guess we'll have to wait and see if Apple will address this in its next bug fix release (10.9). However, by the looks of it, not showing notifications when the app is frontmost is a "feature", so don't get your hopes up.