Guided Decision Table: binding already in use

Description of problem:
In Guided DTs, you can define a binding for a field used in a condition column. After you set that binding, if you try to edit the column again and click apply changes, an alert appears blocking the change: "That binding is already in use by another Pattern or Field - please pick another". Even though that binding is used nowhere else.

You have to remove that binding to be able to proceed.

Version-Release number of selected component (if applicable):
kie-wb 6.0 CR1

Steps to Reproduce:
1. Create a Guided Decision Table.
2. Create a condition column, define a binding on it, click Apply changes.
3. Change the column - add a default value, click Apply changes.

Actual results:
Alert.

Expected results:
Changes applied without problems.