VER 210 Colors problem

[pat55]

Using two different PCs next to each other, both with the exact software, latest win 10 & XY --- one is a 4K resolution.
F9 Configuration on both > Colors and Styles > Colors
IDENTICAL SETTING ON THE TWO PCs

Why such difference between the two PCs - with the tree red on one and green on the other.
Tabs are brown on one and light grey on the other.
(WITH PRECISELY THE IDENTICAL 'COLOR' SETTINGS)
Making all kinds of wild color setting - either does nothing or give unanticipated outcomes. (It favors nothing)

I do a refresh F5 - or restart XY = nothing changes.
What is the secret to all these colors and to display them consistently?
What am I missing?
pat

[Jerry]

Show screen shots of each XY window on the 2 machines, please.