Motorola Droid : Having New Email On Gmail Notification

When I get a new email on gmail, I pull down the notification drop down, select the email then view the email, and out of habit or ease of use, I hit the home button ...because it just makes sense that if I don't need to respond that I want to go back to the home screen directly. Why in the hell does the stupid notification not go away until I check the email 2 times.the only way the notification goes away is if when I select the email to check, I have to hit the back button which takes me back to the email list then either hit back again or home.