Calculation Condition GeoMapping

[MIKIEMILLER]

I have an area layer geomap that has a dimension as follows:

=if('$(vMapD)'='St',[Challenge State],
if('$(vMapD)'='County',[Challenge County]&', '&[Challenge State]))

I then want to add a bubble layer underneath that, so when you select a [Challenge County] on the map, it shows each [Challenge Unit](s) in that [Challenge County].

When I put in the expression below in the Calculation Condition field on the bubble layer, the only way it works is if I make a selection from a selection box and not the map itself. 

=GetSelectedCount([Challenge County])>'0'

Is there an expression that I can put in the Calculation Condition Field that will accomplish this while keeping my dimension an if statement?

[Channa]

try to create variable

vChallengeCountry= [Challenge County]

=GetSelectedCount(vChallengeCountry)>'0'

[MIKIEMILLER · Accepted solution]

Figured out answer.  Need to different area layers, and a bubble layer.