HelpFormatter strips leading whitespaces in the footer

I discovered a bug in Commons CLI while using it through Groovy's CliBuilder. See the following issue:

http://jira.codehaus.org/browse/GROOVY-4313?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel

Copied:
The following code:

def cli = new CliBuilder(footer: "line1:\n line2:\n")
cli.usage()

Produces the following output:

line1
line2

Note that there are no whitespaces before "line2". Replacing them with "\t" doesn't solve the problem either.