Dialog Toolkit in macOS Tahoe – buttons overlap

The new macOS Tahoe changes the appearance of buttons in my applet. The dialog (and buttons) are created using DTP. In Tahoe the buttons are all wider and now visibly overlap. “equal widths” is off.

Is there a way to restore the separation between buttons to stop the overlap ?

Is there a way to do that without affecting users on pre-Tahoe macOS ?

Thanks.