You're getting confused there. One dialog is for editing the appearance of a menu. The other dialog is for editing a button that runs a command. Nothing secret or unusual being discovered here, nor are you looking at the "Advanced" dialog (you get that by clicking the button that says "Advanced" at the bottom of your screenshot).
Your syntax is also incorrect. If you use a = between argument name and parameter, there should not be any spaces before or after it. The command should be either:
Recent PATH "C:\Delphi"
(Quotes are optional if the path doesn't contain spaces, but it's a good habit to include them so you don't have to think about what's in the path.)
Sorry for sinning against the DirectoryOpus syntax rules The syntax I used works despite the spaces (thanks to the built-in syntax tolerance). Thanks for the free syntax lesson, though! However, you should rethink the user interface!
Is it not allowed to make some suggestions? DOpus is an excellent application. But even excellent applications profit from user suggestions. Please don't be offended if a user makes a suggestion. (Perhaps I should change my avatar picture so it does not scare people).