Empty Lines shown in history for "?" key.

[Google Code Exporter]

What steps will reproduce the problem?
1.Press "?" key for getting command list.  
2.Then show history and there you'll find one empty entry for this key/command.
3.

What is the expected output? What do you see instead?
Expected output should be ? instead of empty line.

What version of the product are you using? On what operating system?
1.6.7, Centos

Please provide any additional information below.

Original issue reported on code.google.com by [e-mail] on 13 May 2015 at 6:45