The Line Height Adjustment field is useful in "tweaking" the appearance of your screen so that individual rows do not overlap and/or have the right amount of space in-between them.

 

When using the Web Browser entry field style, this setting can be used to prevent vertical overlap of entry fields on busy screens (where two entry fields are adjacent vertically).

 

Be aware of the fact that the higher you set this number, the taller the emulator window will need to be in order to fit the full screen image.