This feature is working correctly as documented. "Also display results from the second field" is pretty unambigous. You're choosing to make your fields smaller than the fill width to display the value, but that's not FileMaker's fault.
One way to get the result you want is to have a two fields stacked on top of each other. One that allows entry in Browse mode with the value list as you have it but with conditional formatting that sets the font size to 500 px when there's a value. The other field would be the exact same field, but not be enterable in Browse mode, and not have a value list attached.