Works fine on my end using Asus VP28UQG 4K and Windows 10 without any scaling issues. From MT4 build 940 it began supporting 4Kthomdel wrote: Sun Jun 02, 2019 2:21 am Can Seniors / Members / Traders Please Share Their MT4 Experience / Compatibility on 4K / UHD Monitor running Windows 10 System ?

As quoted by MetaQuotes regarding 4K support since build 940:
MetaTrader 4 build 940: Optimized for ultra-high-resolution (4K) displays
Release Notes: MetaTrader 4
11 December 2015
Terminal
The terminal interface has been completely adapted for ultra-high-resolution (4K) displays. All user interface elements are properly displayed on large screens. On smaller screens, the UI elements are automatically enlarged for better readability.