However, if you try to perform a lookup in the Workflow User Selection to select an approver, you will get a result of No results found:
The reason for this, is that the AD Group needs to have a Display name set and this is not available via the New Object Group or the Properties window.
Instead, you need to enable the Advanced Features in the Active Directory Users and Computers window by clicking on the View menu and then clicking Advanced Features:
Right click on the Group which needs a Display Name and click Properties:
Click the Attribute Editor tab and then select the displayName attribute and click Edit:
Enter the display name in the Value field and click OK:
Click OK to save the change:
Now when you do a lookup for the group in Workflow User Selection the group being searched for is correctly returned: