I have Pro X v16.3, v17.0 and v18.0 installed on a 24inch 4k Dell AIO with 150% scale-up.

The icon issue in the dialogue box to which you refer, I do not believe, will be resolved by any Windows10 setting, I have exactly the same issue - v18.0 introduced HiDPI and I understand the difference we see maybe related to the application not seeing ALL the icon sizes required by Windows to support HiDPI. The full set of icons would have 16px, 32px, 48px, 64px, & 256px bitmaps. The original HiDPI beta tests did identify a few similar issues that were fixed before release. Could be completely wrong here, but experience from building apps to run with 4k scaling suggests this could be the root cause.

That said, I can live with the issue and for me v18.0 with HiDPI support is a solid upgrade from v17.

Gary