When you assign a choice list to a field, 4D automatically presents the choice list any time you click into that field. You may also notice that those particular fields will only accept data from the choice list. You won't be able to enter data manually. To allow a user manual input, you must follow these steps:

1. Go to the Design Environment.
2. Under the Tools menu, select "Explorer".
3. In the Form tab, open the form editor by double clicking on the input form or by clicking once on the input form and then clicking the Edit button.
4. Click once on the field that is associated with the choice list.
5. Under the Form menu, select "Display" and select either "Property List" or "Object Properties".

If you select the "Property List", uncheck the "Tabable" check box from the Object category. If you select the "Object Properties", select the third tab from the left and uncheck the "Tabable" check box in the "Object Attributes" area.
For more information see "Creating an Active Object" in Chapter 5 of the 4th Dimension Design Reference:

4D V6.0.x Design Reference (PDF format / 13.3MB)
4D V6.5.x Design Reference (PDF format / 10.9MB)