Relative Date not showing in Slicer visualization ... (Power BI service)

[Anonymous]

I have a date field, which contains all dates... If I drop it onto a report, and set the visualisation to slicer, the only options I get from the drop down are 

"Between"

"Before"

"After"

"List"

"Dropdown"

(all of which work fine/as expected)

I was expecting to see "Relative"... what am I doing wrong?

(This post seems to indicate that it should be possible)

Thanks,
Ger