Yeah I thought the same thing - what tabs?
Go to settings, then under device select "Application Manager".
Then select the menu button in the bottom right of the screen then select "Reset default app" and all of the apps that have been set to default will show up.
You select the ones you want reset.
I had accidentally picked VZ navigator as my default and I wanted it to go away. I selected it in the list and now I can choose my default again when I use Google maps.