My Windows desktop project uses flexible scrollable forms, and I managed to make these forms scroll quite well using 2017R3. ( = D2D). I followed the instructions of @ and the guidelines published by @Paul Lefebvre a couple of weeks ago.
You can download a zip with two short movies here. One showing a long scrollable form as I us it now, and one scrolling the same form build with 2018R1.1, both 32 bit on Windows 10. Building 64-bit (default or aggressive) shows the same results. (2018R1.1 uses LLVM 6 I suppose).
Don’t know what I can do more than just sticking to the 2017 release since what I see with 2018R1 is not salable to any end-user, and I don’t want to leave the concept of scrollable forms since it give me ultimate flexibility.