set default value for drop down select

Dear All,

I would like to create a custom form for changing application sensitivity. I get the current sensitivity with a "drop down select with webservice" field and also there is a "drop down select" field for new sensitivity with values A, B, C, D, E. I have set the drop down field's default value to current sensitivity (see on screenshot) but when running the form it will be defaulted to "A".

I can use current sensitivity as default if I use a text field for new sensitivity but it was customer's requirement to use a drop down.

Any idea how to change default value? Even <empty> would be acceptable.

Zoltan