Workflow and Node variable definitions are not correctly updated on Designer

When a workflow variable or a node variable is defined in Modeler, any changes on the field type is not propagated in Designer. For exemple, a user define a workflow varibale called "approvalComment", then activate it on a task, and generate the layout => the approvalComment is a nuxeo-input in the workflow layout talk as expected. But if the approvalComment workflow variable is set to multi-valued, then if we go back to the workflow task layout to update the element => Nuxeo Studio Designer still displays a nuxeo-input instead of a data table (it is quickly identified as the field is not marked as a table.

The only solution is to remove the field from the layout, remove the workflow variable from all tasks using it in Modeler, then Save, then activate it again.