Anyway, for me it remains a Xojo bug.
Disabling touchpen processor is not a real fix ;-).
Thnx for testing. (i copy your feedback to the case)
So it seems a bug on windows touch (pen) enabled devices.
Checked with:
Surface Pro 5
Surface Laptop 3
Surface Go
Samsung Galaxy Book Flex
(all touch AND pen devices)
I am not assigning the bug. Just figuring out why some say it works, some say it does not. I was able to find two contexts where it does not work and a few where it does. That is where I stop. No speculation (but I do indulge in speculation more often than I should) My Surface Laptop 3 is usually with both touchpen and touchscreen off. I hate with a passion dirt and fingerprints on my screen… 
I’ve asked Andreas to create a new case containing the updated and corrected information.
Personally I cannot replicate this issue using my Windows touchscreen laptop (a Sony Vaio).
Looking into ways to workaround that.
Done
<https://xojo.com/issue/64545>
If you need, i can give you remote access to a surface device for testing.