Leaderboard

Use the standard system dialogs. They will work with any version of Windows and, most importantly, look and function like the users expect them to. For example DevExpress have begun using their own custom dialogs in their skin editor and in their design-time editors and it's just horrible. The dialogs are skinned even though nothing else is, the usability sucks, lots of things just doesn't work and the usual explorer integration that comes for free with a standard system dialog doesn't work properly, etc. etc. Is there any particular reason why you want to use a custom dialog? Based on the visdom of fortune cookies and my magic crystal ball I foresee that your as of yet unknown changes will lead to as of yet unknown challenges. You're welcome.

Have you checked the possible reason stated in that message?

One of the regular attendees of the Oregon Delphi User Group did a lot of research last summer on this very issue because he had the exact same problem you have. We were meeting virtually and actually recorded this particular meeting. You can view the recording and listen to his explanation and complete solution in the first 25 minutes of the video here: https://odug.org/2021-06

There's nothing better than good old classic