I have found out the hard way that there is a timer on edits within
the Consortium wiki software. If you are actively editing an item and
if the edit is not completed in a fairly short time, you will be
logged off and the edit changes are lost. I don't know exactly, but I
think this timer is in the 20 to 60 second range.
There is a description of a workaround using Show Preview here:
http://en.wikipedia.org/wiki/Help:Show_preview