Use Variables in "Filter data by value"

Hi,

I tried to use the “Filter data by value” from the “Transformation types and options” in my table. I’d like to match the data against a variable (Host) the user selects via a dropdown box.

Unfortunately this does not work. Entering the value directly works. What is the notation here? $Host, ${Host}?

Or is it not allowed to use variables here?

thanks
Horst