OK, I complained the other day that I missed Tab Mix Plus.  Then I found an answer on this forum - Sets of related tabs in multiple windows.  Multiple folders with related sets of tabs in each one.  Put the FOLDERS on the bookmark bar.  Open each window with its tabs from there using “open all in new window.

However, continually clicking down in the tray to open one or another of my windows got old real quick and the solution was so obvious it took me two days to think of it. 

Change the size of each window down to, oh say, one sixth of your total OS window and just line 'em up two rows of three.  You could use a smaller size if you have more  folders  Then it's merely a Click on the 'restore' button (upper right corner middle buttton) and you're in business.  Open one full screen, shut it back to one sixth size when finished, open the next one.  Select one tab in the set that will tell you what the tab set theme is.  For example, on my “News” folder window, I chose a news source that shows it's logo in the upper left of the page and will be visible in the small, resized window.

Preserve all of this with the windows 'hibernate' function.  Instead of completely shutting down, just set the off button to hibernate (there are instructions elsewhere on the net to set this up).  The next time(s) you open your computer, all comes back as it was when you 'hibernated'.  CAUTION:  about once a week or more often depending on your rate of use, the computer needs to be shut down normally to clear some files out, such as the DNS file, to keep the load from slowing your computer down.  There are other reasons for completely rebooting once in a while, but sufficient to say:  Just Do It.

same here bro..whenever i open more than 3 windows..it pc get hanged…so i m also avoiding more windows….