Can I show a UI in the Custom Action/Custom Activity using the Execute method implementation?(I am not talking about the Configuration Pages - that is clear. Asking about presenting a UI with TextBoxes, DropDown List, CheckBoxes, Radio buttons etc. for inputs and a couple of buttons for different actions at runtime when the custom action gets executed.
How would I do it? Using Nintex Form? Confused about what is the best approach. Is it better to create a Custom Task and not a Custom Action?