Description of problem:
In GDT, if operation 'is contained in the (comma separated) list' is selected, Editor is not displayed (White page is shown).

Here is example of problematic source DRL.

rule "Row 1 gudedDT1"
    dialect "mvel"
    when
        f1 : Claim( product in ( "EAP" ) )
    then
end

//from row number: 2
rule "Row 2 gudedDT1"
    dialect "mvel"
    when
        f1 : Claim( product in ( "BRMS" ) )
    then
end



Version-Release number of selected component (if applicable):
6.2.0/6.1.0

How reproducible:


Steps to Reproduce:

1. Create fact: Claim (product: String, solution: String)

2. Create enumeration like the following

   'Claim.product' : ['EAP','BRMS']
   'Claim.solution' : ['1','2']


3. create new guided decition table by checking 'Use Wizard'

- Option "Use Wizard": checked
- Option "Extended entry, values defined in table body": checked
- Screen "Imports": leave default
- Screen "Add Fact Patterns": choose "Claim"
- Screen "Add Constraints": 
	- choose "Claim > product"
	- column header: "Product"
	- operator: "is contained in the (comma separated) list"
	- calculation type: "Literal value"
	- default value: "Choose..."
- Screen "Add Actions to update Facts":
	- choose "Claim > solution"
	- column header: "Solution"
	- default value: "Choose..."
- Click "Finish"

Actual results:

Editor is not displayed in Editor tab(White page is shown)


Expected results:

Editor is displayed


Additional info: