GDT: when adding condition, user must reselect calculation type

Description of problem:
When adding a condition column in the Guided Decision Table, you have to set a fact pattern and choose a calculation type, before you can choose a field.
The calculation type selected by default is the Literal value. If that is what you want, you'd just go directly to field selection, but it is disabled until you click some calculation type, even if the default is already pre-selected.

(Other columns seem okay.)

Version-Release number of selected component (if applicable):
BPMS 6.0 ER4

How reproducible:

Steps to Reproduce:
1. Create a new GDT.
2. Add a new condition column - select fact pattern.
3. Try to choose field without changing the calculation type from the default Literal value.