A field called "Date" does not exist, selections are actually made in the underlying field(s) you are using in your expression. You should "scope" your expression with an aggr() and a fieldname. I can't tell what fieldname you are using in your screenshot, but as an example I'll use "ShipDatetime". Then your expression should be:
Your current selections bar would then show selections for the field "ShipDatetime". See Scoping Selections with Aggr() | Qlikview Cookbook for more info.