[xwiki-users] how to set "Join separator (for display)" to be newline?

In a multiple select item in a class definition, how do you set the "Join separator (for display)" to be a newline? -- Mark Wallace Principal Engineer, Semantic Applications Modus Operandi, Inc. CONFIDENTIALITY NOTICE: The information transmitted (including attachments) is covered by the Electronic Communications Privacy Act, 18 U.S.C. 2510-2521. This transmission is intended only for the person(s) or entity/entities to which it is addressed and may contain confidential and/or proprietary material. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient or have received this transmission in error, please contact the sender by reply e-mail and destroy all copies of the original message.