i am not finding it

OK, here goes. I'm on Linux; location of the settings menu may differ, depending on what you use.

- Go to Tools menu, select "Add-Ons and Themes". You can also go to about:addons in the URL bar.

- On that page, I have on the left: Recommendations, Extensions, Themes, Plugins. Choose Extensions.

- You should be in a page that says, "Manage Your Extensions" near the top. Scroll down to find the one in question, Sidebery in this case.

- To the right of the enable/disable toggle, there is an icon with three dots.

- Click the three-dot icon, select "Manage".

- One of the options is, "Run in Private Windows". Select "Allow".

If I open a private window, Sidebery isn't open by default, but is available if the extension icon is clicked in the bar under the tabs, or I click Ctrl-e to toggle back and forth.

Hope this helps!

i have that. i know about that and that is not my question.

what i am saying is, when i open a private window, sideberry does not auto start. I have to press ctrl-e to open it. then it can work as expected.

in normal window (which i dont use) it persists across new windows so i am suspecting this is a bug

Ah, OK. I would just hit ctrl-e and move on, but that's just me.