I have upped the timeout value to 6 hours, which will cause this "soft" timeout after 4 hours of inactivity. I believe this is pretty close to what we had before. I am going to test this tonight, but the problem should be fixed now.
I guess that adding warning about session timeout to text that normally appear in a Edit mode can prevent future problems with contributors caught by surprise. If there is no objections I'll try to find proper files in Mediwiki space and add sentence.
I don't see any problem with it, although I don't know if it's necessary. The wikis have always had a timeout like this, and I am unaware of any complaints except for this one, and only because the timeout was set to such a low value. However, I'm willing to concede that we have some very dedicated editors who may take more than 4 hours on an article :) By the way, I have confirmed that I stay logged in after an hour of inactivity, so I think we are good on that issue. -Matt