MX-1 Shutter

In the MX-1's Menu C2, item 7 is "Electronic Shutter" and its default setting is "Disable". I can't find anything informative about it in the manual. Does anyone know what this feature is, and in what circumstances it should be enabled?

Thank you in advance for your helpful replies.

Cheers.
Philip

This is explored a bit on the US forum:

http://www.pentaxforums.com/forums/7-pentax-compact-cameras/233928-question-mx-1...