You need to be in DTX Builder. If you're not, rightclick on the DTX icon in the systray and select "Switch to DesktopX Builder".
Once in Builder, right click on the DTX systray icon and select "List Objects".
The Navigator window that comes up may not show the window buttons in the top right (not really Win10 compatible). If you click in the top right corner where the close button should be, it'll close. You can also rightclick on the title bar and get the min/max/close options.