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: