Microsoft Excel CHART question
 

I would like to be able to NOT SHOW empty cells in my excel graphs, but
because they are filled with a formula, they show up. When I go to: Tools,
Options, Chart, Active Chart...the area to work with this issue is GREYED!

Can anyone tell me why...and how to turn it on so I can manipulate what
cells show up in my graph?

Thanks for any assistance
--
Wanda