Cursor control in "Prompt for user input" action

I have a macro set up to start German emails with Hallo xxx where xxx is either the first or family name of the E-Mail recipient (fetched by an Applescript) depending on how well I know them. This is decided by a prompt which asks me if the address form is "deine" or "Ihre".

When the prompt triggers, pressing the down arrow key causes the selection box to drop down (see screenshot) but I can't move the cursor to the next option using the arrow keys. When I need the second option, I have to grab the mouse and select it then click OK.

Is this a bug or is there some way of getting the keyboard to move the cursor? I've tried tab which does work but moves the selection to the cancel button, then ok and back to the dropdown.

Seems to be the same problem discussed here Popup menu in Prompt for User Input problem

Thanks for pointing me to this. I did try searching for “user input” but didn’t see this. The Ctrl key option seems to work for me.