[DMN Editor] Add support for deleting expression type and revert to 'Undefined' -------------------------------------------------------------------------------- Key: DROOLS-2353 URL: https://issues.jboss.org/browse/DROOLS-2353 Project: Drools Issue Type: Sub-task Components: DMN Editor Reporter: Michael Anstis Assignee: Michael Anstis Various Expression editors allow for nested expressions. Once a nested expression type has been set it is not possible to change it.