Henk Westerhof, Amsterdam, The Netherlands (email@example.com) produced a simple window to demonstrate this. It combines a textbox and a list so that the list's choices narrow down as you type in the first characters of the item you're seeking. He's generously offered it to the WS user community and I'm pleased to publish it here.
Download HandT011.VEX using the hyperlink, saving the file as text. Then import it into Workstation.