Because an edit box uses up some space drawing its border, and due to the varying factors which affect font size, you may find that your edit boxes are too small to either fit the editing font, or to see the editing font if it does fit. The example below illustrates a borderline case, where the characters are not being clipped, but we are still getting little tick marks along the baseline of the edit box due to the cursor and/or tails of characters intersecting the edge of the box.
To alleviate this slightly, we’ll set this option, which will cause the edit controls to use up to half of the leading space to make the control a bit taller. (This requires, of course, that you set your external leading to a non-zero value, preferably something like 6.) This provides a slight improvement: