I have the issue on a iMac 5K (with intel i7 with AMD GPU) and a new Asus laptop with i7 and NVidia GPU. They are beefy enough I guess. 
[quote=204543:@Christoph De Vocht]I am not running Windows 10 in a VM.
I see the issue with my iMac 5K (with bootcamp) and my daughter Asus laptop (current model bought in februari 2015).
The user who complaint is running a custom PC with AMD cpu and AMD graphics. If Xojo Inc needs the full correct spec of that user, I can ask him.[/quote]
To all (who can do that): can you boot directly in the Windows 10 DVD and check if the trouble still exists ?
Perhaps certain hardware and chipsets? I just tested the theory using a VM and reduced the specs to below the minimum with no issue. It crawled, but no flicker. Will venture over to MSDN and see what others might say. It’s definitely not limited to Xojo. Xojo is not the issue.
All,
I am running a Microsoft Surface Pro 3 with the Windows 10 RC and having the exact same issue with Xojo 2015 r2.2.
If you run your mouse over close, minimize, maximize of Xojo itself… you will see the flicker. From what I can tell, flicker occurs during movement of the mouse.
Also to add, if I launch Visual Studio 2015 Community and create a Windows Forms Application and click run… It does not flicker on the buttons.
Found some more info:
If you force your compiled Xojo app into HDPI mode (right click and set enable this in the Compatibility tab) it does not flicker.