I want to add a new notification. I click on add, navigate through the myriad (punch) of Events, find the one I want and click on next.
As I don't have the logic for the filter in my brain, I open a second window.
In the second window I open another, well-set-up notification to check for the filter syntax. Once understood, I close this new window and go back to my new notification.
I enter the filter and click on "next".
I find myself now in the final dialog for the Notifications and the form features all the information of the second notification I opened to check the syntax.
I ignore that, make my changes and save.

The result is that my new notification is not created but that I now modified the old notification I used as reference.

I'm using IE6 right now.

My conclusion is that it's not possible for a user to edit multiple notifications at the same time, nor to even open a second one. Seems that the "last opened" notification overrides what I did before.
The root cause could be the session management?