Tabs can only be opened in a new session

Paid User issues - Tabs Outliner seems to work very well for several months, then lose its mind and become a mess.  

Specifically, I cannot open any tabs by double-clicking them.  

I have hundreds of tabs, organized into groups.  When I want to open a tab I go to the relevant group and click on it.  Many of these are things I use daily, mostly spreadsheets, etc.  

This no longer works at all.  

Someone suggested this might be because I'd recently added and removed a screen from the PC and apparently the outliner doesn't like this.  

CTRL-Click to open Link in Last Window does not work (nothing happens)

SHIFT-Click to Open Link in New Window does not work (nothing happens)

If I have a NEW window open, I can double click and the tab opens.  But it opens in the new window.

Obviously this completely breaks Groups.  Yes I can salvage my links, but they are now a random mess of whatever I used last.  I'm getting along on an emergency basis, but the amount of work to rebuild each group is staggering, and I'm currently looking for a more reliable alternative with similar features.  

Is anyone aware of:

A) Why this would happen in the first place and 
B) Any way to restore the expected behavior - e.g. I click on a Group, all of the tabs in the group open, I click on a tab in a group, it opens and other tabs in the same group will open in the same window?