2D Text Properties - Line Spacing

[CAD2015]

Hi,

I am tring to increase the spaces between the letters of the text (red circled on the right):

I have successfully done in the past on other files (working on the Line Spacing in text Properties), but I can't do it on this text.
What is wrong?

CAD 2015

 

[dougsnell]

Font Tab > Spacing field controls the Text Spacing with a percentage value