How can i force a legend on line chart with just one expression?

[#1]

Someboby knowns how can i force a legend on line chart with JUST ONE expression.......

i need to show a legend about my unique expression.....

tsk a lot!!!!!

[Anonymous]

Add one more expression, and mark it "Invisible"

[#3]

Good trick!!!!

tks a lot!!!!

[#4]

Michael,

it´s works, but when mouse over the point....the legend show my invisible expression, i try to uncheck text as pop-up but still show a value!!!!!

Any idea?

tks again!!!!

[pover]

Following Michael's advice, I don't see the invisible expression in the pop-up. I'm using version 9 SR 5. The example is attached.

[Anonymous]

Try to use invisible expression wtih empty result and empty label, see if it helps.

[#7]

Tks again Michael.....

I use empty label (space) and expression is SUM(0), if i use empty expression my legend disappeared.

Now work as well!!!