App display groups are a way to visually tie your apps together. If you have many apps, the display groups make it easier to find them throughout the publisher interface. For example, if you have multiple markets, you can search by market in all of the drop-downs below:
As you can see above, we started typing "north" and it showed apps included in the display groups "Northeast" as well as the app "Northern Fisherman" which is not in any display group.
Apps do not have to be in a display group, but if they are, they can be in only one. App display groups have no impact on user login permissions.
If you have company administrator privileges, you can create and manage various app display groups. Here is how you get to the management page:
Here is what the management page looks like. After modifying the list of apps, simply click "Save Changes" for the corresponding app group row.
Remember, an app can only be saved in one group. If I was to add "4TC" to the "Midwest" group and hit "Save Changes" it will in turn remove it from the "Northeast" group.
Note: After modifying app display groups, you must log out and then back in to see the changes reflected in the drop downs throughout the web interface.