How to edit text in text line?

Hi,

I am a musescore newbie, I am sure that this capability exists but I have not been able to figure out how to do it after searching the documentation, forums, and the program menus...

I am trying to use a "text line" to indicate the position of a barre in a guitar score. In the line palette, the text line is shown as Roman numeral VII, followed by a line on the right with a down-turned hook at the end. This is exactly what I want, but I want to be able to change the Roman numeral. Double-clicking the text or line lets the length of the line be changed, but I can't figure out how to change the Roman numeral to something different.

I am using MuseScore 1.3, rev 5702, on Mac OSX v. 10.8.5

thanks in advance,
Jeff