Selection of the object clicked during a window activation

On Mac, for the Finder, I noticed that in list view, clicking (which activates the window) on a list item does not select it.
On the other hand, in icon mode display, the window activation click selects the clicked icon.

How to do the same with Xojo? The Activate event does not include a Boolean return, which would allow the click to be intercepted so that it does not select anything behind.

Thanks for your ideas