Cascading Dropdown

Hello,
I have read the information on conditional and cascading dropdowns.  I'm wondering if there is a different way to accomplish the data entry illustrated in this example. 
On a single form, we would like user to be able to create and add events, enter various data about the event, choose a Category for the event from a dropdown list, then choose a Subcategory from a dropdown list that is dependent on the Category chosen.

So far I have
- Category and Subcategory tables related to the parent tables (one to many) and to each other
- a grid edit form with the Category dropdown working properly
- but the Subcategory dropdown shows <Browse Choices> instead of the desired list of Subcategories, when <Browse Choices> is selected a pop-up window displays instead of a dropdown list.

Is there a way to get the conditional dropdown menu to show up in the grid edit - perhaps using a different method completely, such as shared fields?

Thank you!

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Anne-Claire Markle
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