If I create a new select component, use "Load a pre-built option list", and use a pre-built option list that contains a group, Options Element does not display properly because it is configured to not allow groups. The problem is that #optgroups is set based on the value of aslist, but this doesn't get updated when one chooses the pre-built option list.
The attached patch fixes it by always setting #optgroups to TRUE. This is fine because the user is always allowed to use groups. Current behavior already is that if the user uses groups, then aslist is set TRUE when the component is saved.