New tabs are child of window, not child of parent tab

Summary:
new tabs always appear at top-level under the parent window, not the
tab that I opened it from when doing 'Open Link in New Tab'.


background:
Last week after having chrome running for over two weeks,
and reading about some chrome update (after google i/o) and seeing my
chrome was not up-to-date, I decided to restart.

Everytime I started TO it would crash.
I looked up the problem in the forums here but the solutions didn't help.

So, I spend way too much time and reverse engineered the format by
creating a new chrome user and looking at the TO file there.
Then I wrote something to split up the TO file from my 985 windows
into more managable pieces (windows 1-100, 101-200, ..., 900-985) and
renumber them so I could save them as html.
[I'll write more about that in another message, time permitting.]

Instead of starting from scratch I started with the last set of 86
windows, which went back over a month, and I can access the html file
if I need to.

I would start from scratch, but drag-n-drop from saved HTML doesn't work on the Mac (?).
It looks like the entire tree is dragging over, but when I drop in Tabs Outliner it
creates a note entry with text like:

<meta http-equiv="Content-Type" content="text/html;charset=UTF-8"><!--tabsoutlinerdata:begin{"type":"link_","title":"awscli - Google Search","url":"https://www.google.com/search?q=awscli&oq=awscli&aqs=chrome..69i57j0l5.3535j0j7&sourceid=chrome&es_sm=119&ie=UTF-8","subnodes":[{"type":"link_","title":

(probably truncated because note can only be 300 characters)


Problem now:
new tabs always appear at top-level under the parent window, not the
tab that I opened it from. What would cause that?
Also, 'expand all' usually causes tabs outliner to crash, so I suspect
there is still some slight corruption.

Note: crossposted at
https://groups.google.com/forum/#!topic/tabs-outliner-support-group/23_UU1-4Ybg
I just found about userecho.