Total Text Container was mentioned in a reader's comment in this post http://www.wordyard.com/2006/07/26/outliners/ in Scott Rosenberg's blog, to which I was lead from Manfred's blog. That's just about all the background I have on the program, which is a two-pane outliner whose information items can be anything from text, to a spreadsheet, to a contact database record to a calendar entry...
http://mtirnanic.googlepages.com/

I am impressed, but have no idea whether it is still being developed (the original comment was from 2007) or what potential issues it could have.