https://bugs.winehq.org/show_bug.cgi?id=48640
--- Comment #2 from Albert Wiersch support@htmlvalidator.com --- The person helping me with this confirmed that functionality works in Wine 5.3 Staging. The toolbar issue still exists (see https://bugs.winehq.org/show_bug.cgi?id=48633 for toolbar).
However, the rendering is poor. See Wine5.3Staging-task1.png (immediately after clicking the green "Add Target" icon in the toolbar) and Wine5.3Staging-task2.png (the mouse pointer hovering over the "Add URL target" option. No option has been clicked).
More details from person checking this for me:
Good news -- it does work under Wine Staging 5.3, though there is an issue with aesthetics. The "Add file target(s)" option is pre-selected, and that displays poorly. If there were no pre-selected default, it would look and work great. Hovering over a button with the mouse pointer raises a highlight, as intended, though that does not happen for the pre-selected "Add file target(s)" button. Clicking any of the three options, including the pre-selected "Add file target(s)", immediately opens the appropriate dialog. Functionality is great, but looks a bit weird, especially when the "Add what target?" window first opens -- kind of a "What is that?" moment.
If removing the pre-selection from the "Add file target(s)" isn't possible or does not work, maybe remove the green right-pointing arrows and make all three options buttons in the same style as the pre-selected "Add file target(s)" button. Or anything else that makes all three buttons look the same when the window first opens.