Showing a window at launch prevents access to main table view

I am developing a chat application for Mac. Once I log in into my application, I get a notifica开发者_运维知识库tion window showing the users who are online. I am controlling the fade in and fade out effect of this window using an NSTimer. My problem is that until all my notifications disappear, I am unable to access the main table view. I am stuck on this issue. Can anyone help me out?

Can you show the notification window in a background thread? By calling performSelectorInBackground