Validation Error using Intermediate Message Catch Event

[caleeli]

When create an Intermediate Message Catch Event, its is being saved/created with invalid properties that is causing and validation error on saving the xml diagram.

If the Message Event Identifier is empty:

The attribute variableName is not defined in the XSD nor moddle extension, the defined attribute in the PRD and in the latest version of the XSD and the moddle extension is "dataName" so using variableName is causing an validation error here:

PM4-IntermediateMessageCatchEvent-PRD-290519-1556.pdf

[tuantruong625]

@caleeli @velkymx

Data name was renamed to variable name.
Issue: #356
PR: #360

• I can make the message event identifier required before saving.
• I believe this change also needs to happen in processmaker-bpmn-moddle.

[caleeli]

Could be good to have an initial default value for the "Message Event Identifier" that could be "message"