Text Line Height

At the moment the line height feature for two rows of text in a text box or text area only allows you to go to 1 on the scale. Can this be adapted to allow it to go minus (-1, -2, -3 etc) as at present it leaves to much space between lines on some fonts.

The only solution at present is to create another text box to sit below, that way you can adjust the distance between the two which is not ideal.

Thanks.