In the Coordinate System Categories - Manage dialog box, do any of the following:
To remove a category, enter its code or select it in the User Defined Coordinate System Categories list. Click Remove
To change the coordinate systems associated with a category, enter its code or select it in the User Defined Coordinate System Categories list. Select coordinate systems in the Available Coordinate Systems list on the left and click Add to move them to the Coordinate Systems In This Category list on the right.
To remove a coordinate system from this category, select it in the right-hand list and click Remove.
To create a category, click Create and follow the instructions in the preceding procedure.