You can control when choices become available by:
Setting the Sequential property of a Choice object. By default, the Sequential Property is set to True and makes the choice visible to DTCs below it. Setting it to False makes the choice visible to all the DTCs on the same page.
Note This assumes that you have designed your DTCs in such a way that the user knows when to use them and positions them properly or that the DTC handles errors when it is inappropriately placed on a page.
Warning Allowing choices to be visible to all design-time controls in the document can lead to cyclical references. For example, you can create three DTCs and make the first rely on a choice in the third control, which relies on a choice in the second control, which relies on the first control. This creates an infinite loop that stalls the hosting editor.
Setting the Enabled property of the Choice. A choice can be enabled or disabled through its Enabled Property. Disabling a choice notifies all sinks that were bound to the choice that it is currently unavailable. Enabling the Choice notifies the ChoiceSinks that the choice is available.
Revoking a Choice. Using the Revoke Method, you can destroy the Choice and notify all ChoiceSinks that were bound to it that the Choice is lost.
Applying a filter using a ChoiceFilter. For more information about using ChoiceFilters see Subscribing to a Choice.