That setting changes the font for the password in a specific entry. It does not change the font for the master password, entered on starting PWSafe.
I've just moved to a new laptop with a high DPI screen, 2880x1800. Password Safe works fine, except for the login dialogue: the font size for the master password entry screen is very small. I've tried changing ther values for high DPI in Properties->Compatability, but it has no effect. Any suggestions please?