Your comments

This is the Tabs Outliner Tree page url:
chrome-extension://eggkanocgddhmamlbiijnphhppkpkmkl/activesessionview.html
You can open it directly from shortcut for example
Cannot reproduce this.

In any case Tabs Outliner does not have code which load any other windows or tabs on start, except maybe own tree view, if such option in TO is checked.

Are you sure that Chrome settings are set to "Open the New Tab page"? It's more looks like that the "Continue where you left off" is set.
Yes, there is several options to rescue.
The best one of course if you have a backup of a system drive...

But even if not, there is still some possibilities.

First of all, can you explain how exactly looks this TO had absolutely nothing in its history - is they not start, or what?

Also maybe it's better to switch to email
please send me a content of the next page 
chrome://version/
to vladyslav.volovyk@gmail.com

Also please go to 
chrome://extensions/
select Developer mode checkbox in the up right corner
then navigate to Tabs Outliner entry, click on 
Inspect views: background page
and send also the content of console (last menu item in the window which will open)

Also, i must warn, we there in Ukraine now have a very intense situation, and i might actually answer with a big delay because of this... but we will try to restore your data.
Yes, such problem exist. I sometimes also annoyed by this behavior.
Need to think what will be the best way to deal with this problem, i for example thinking about adding a separate history list for tabs in Tabs Outliner.

Also there is already implemented yet not released meantime possibility to view tree in any point in the past, a history view of the tree. It will of course not a solution, but at least information will not lost and can be easily restored by dragging from history view to the current view.

Take note that there is 2 additional ways to restore tabs without affecting the source hierarchy.
  1. You can alt/ctrl drag the whole hierarchy - this will create a copy, and then restore the copy.
  2. You can shift/ctrl click on tabs and this will restore a link in new window (shift) or as new tab in last selected window (ctrl), without affecting and activating the source node.
Yes, such problem exist. I sometimes also annoyed by this behavior.
Need to think what will be the best way to deal with this problem, i for example thinking about adding the separate history list for tabs in Tabs Outliner.

Also there is already implemented yet not released meantime possibility to view tree in any point in the past, a history view of the tree. It will of course not a solution, but at least information will not lost and can be easily restored by dragging from history view to current view.

Also take note that there is view additional ways to restore tabs without affecting the source hierarchy.
  1. You can alt/ctrl drag the whole hierarchy - this will create a copy, and then restore the copy
  2. You can shift/ctrl click on tabs and this is also will restore the link in new window (shift) or as new tab in last selected window (ctrl) without affecting and activating the source node.
Auto-scroll was cool idea but i found that i don't use it at all.
I recommend turn it off through the options completely.

Well, after reading everything that you wrote i must say that i must agree with everything.

- The dot button is really somewhat "hidden"
- Mode without "wires" really reduce visual clutter (i tried this, it's looks really cool, and future version will contain such theme, but actual use WITH wires is more usable, as it is the drop target, maybe worth to make them just  less visible by default, or show only on drag)
- 2 steps delete process - interesting.....

Well, all of this feedback I really appreciate. Through what to do with all of this i meantime not very sure. There tons of such small tasks that must be done, and many of them have much higher priority and really critical.

Thank you anyway.
Thanks for good words : )

I really thought a lot about things that you wrote.

Meantime the most important problem through is to fund the future development. Read - introducing some paid version, with additional features.

After that i will return to exchanging user experience and so on, there is really a lot of what can be done.

Also i find that actually user is not as dumb as we, the developers, sometimes think. Yes, the first experience is overwhelming, but it is just because nobody in general do not expect such complex things from the regular Chrome extension. Other from this expectations mismatch the tool is not that complex at all.

And yes, the help and introduction is really badly written and not very structured - it must be rewritten completely and reduced. Also some UI changes might really make first experience smoother. But as i said - that is not the most important problem now.
Next version will have a possibility to connect an external css themes. This will give possibility to experiment with different placements and so on.

Really left positioned vertical toolbar is an interesting idea. .
Just drag and drop the hierarchy from saved html file back to main view, or use to reopen links directly