Now if I click on Closed Tabs List to open one I get a blank untitled page??
I'm not sure what you're getting. If I close a tab, then click the Undo Closed Tab, I get the one I closed. But I don't doubt something happened. Like I say, every userChrome mod I tried has done something negative as well as positive. I just haven't found the negative on my system yet.
You should post on that thread with the guy who posted the userChrome mod. Maybe somebody knows a fix or that there isn't one(which would be my guess.)