The first thing to understand is that a choice component can only be populated from a column - not from a row. What you are trying to do won’t work. You need a single column with a choice in each row.
With that said, it is possible to build a dynamic choice list. Here is how I have done it:
- Start off with a single choice, call it ‘Other’
- Add two input components:
- A choice component, which uses your choice list as a source
- A text entry component
- The text entry component should only be shown when the user selects ‘Other’ from the choice component
- Whatever the user enters into the text entry component is added to the list of choices using an Add Row action