How to hide label for one combo chart measure

[GanCW]

I am using a combo chart to display volume and % meeting SLA.  I would like to display a reference line (80% SLA) but Combo chart does not support reference line

I tried adding the SLA as a measure but I can't get rid of the number. 

Any suggestion on how I can display a reference line for combo chart ?

[rubenmarin · Accepted solution]

Hi, you can try using Dual('',Expression) and using 'Measure expression' as number format, this should hide the number

[GanCW]

Thanks, that works, though it would be better if the chart can support a proper reference line.