Suggestion:

When creating a segment, the name can not contain spaces or special characters.  Waiting until the segment is saved to display a notification is not a great user experience.  I recommend providing validation when the user's cursor leaves the name field. 

Additionally, consider using notifications to let the user know when something is not as expected.  Displaying "general information" using a red notification causes the user to check the notification when it is not necessary resulting in unnecessary extra clicks.  The user will most like always check to ensure everything is working as expected and the experience is not positive when it is an informational notification.