Hi runxel,
Thank you for sharing the issue, and I am very sorry about the experience!
Same as you, I was able to replicate this issue on a 4K laptop screen with 200% scaling. I believe to solve this issue, we will need to revamp this dialog, as I can see that the same issue happens with the Expression Editor dialog (super small text at 4K screen). In the meantime, I suggest zooming in the fly-out message (by hovering the mouse over the dialog, Ctrl + mouse wheel, or pinch-to-zoom with trackpad). This will help to enlarge the text.
Thank you very much for your understanding, and I am very sorry for the inconvenience!
Best regards,
Minh
Minh Nguyen
Technical Support Engineer
GRAPHISOFT