> Yes, you would need to follow a common drag-and-drop protocol.
> I don't understand why that is an issue if that is what you want
> to do.
Wasn't that something _you_ wanted to do? If not then we can obviously
ignore it.
>> At least for top-level windows. This will work as long a child windows
>> are fully contained by their parents which IIUC is not necessarily true
>> for macOS systems.
>
> Could you give a concrete example of where this might be a problem
> so I could test code against it?
Hardly. Child windows are a separate problem because, for example, on X
you currently cannot drop files on them - the drop goes to the parent
window instead.
>>> and (2) a function would be needed to get the attributes of
>> those windows.
>
> I have figured that part out from the macOS APIs.
Window attributes are a problem on X. You will learn about that as soon
as you try to adapt your code for it.