SSRS Report hide tablix

Hi

I do have multiple tablix on my SSRS Report and on special conditions I want to hide one of it. Therefore I add an Expression in the tablix properties  "Show or hide.."

this Expression Looks like:

=iif(Fields!SalesOriginId.Value = "01"And Fields!SalesPoolId.Value = "05"And CountRows("WMSPickingList_TransportTmp") > 0, false, true)

So the Tablix should be hidden if the SalesOriginId != "01" AND the SalesPoolId != "05" AND if there are no rows/records in the table the tablix belongs to (WMSPickingList_TransportTmp)

In our case the tablix is shown anytime even if the it should be hidden