Parentheses around chord names above staff?

[wakyct]

hello all,

First time posting to the list, I've used Denemo for a couple of scores now and I really enjoy it. I'm hoping someone can 
advise me on how to add parenthesis around chord names above the staff, this is a common mark at the end of jazz lead sheets. 
For example, I want to typeset (G-7 C-7 F7) parens included above the staff over three measures.

I've searched Denemo and Lilypond docs and while there's a lot of info on parenthesis in the staff, I can't for the life of me 
figure out the solution above the staff.

I tried inserting a text mark above the staff, and that prints the paren in the print view, but I can't drag the paren to 
position it properly (even if I click on typeset in the print view -- maybe I'm doing it wrong). The little hand cursor shows 
up, but nothing happens when I click on the paren.

Thanks for any help, George