kanaka/noVNC — pull request #135 by KarimAllah (2012-03-06 14:42:51+00:00)
Title: Tiny fix for cases when 'alt' or 'ctl' is stuck at 'keyDown' when the window loses focus.

http://www.fifi.org/doc/vnc-common/faq.html
Check question: 'The keyboard doesn't work / keys do strange things!'