Hello! I have just tried to install the addon from store, but I did not notice any extra windows. Can you tell more about this browser window? And is this repeated after each installation?

I did not notice it until after I installed it, later in the day. What it seems to be is a sync or something that is initiated, by what I speculate is the addon. I removed the addon and have not seen the window appear again, now I installed the addon anew and waiting to see if it appears.
The window I mention is not appearing maximized, it is minimized in the taskbar. I only noticed because I have multiple monitors, and have my Firefox on my 2nd monitor. The window that appears flashes only on the primary monitor's taskbar. It remains for about 2 - 4 seconds and disappears. I do not notice this during installation, only while using Firefox and appears throughout the day even when Firefox is open, but not currently being used.

I captured a screenshot of it just now. I noticed the window is labeled as "Device ManageR"  just like that...  I have attached the image here.

When I was clicking on the window to maximize it, nothing happened. I could not get anything more from this than what is in the screenshot. It stayed on my screen this time for about 10 seconds, which is the longest I've ever seen it.

+1

This is an auto-update of dials in the background. It is all right. If you want, you can turn off an auto-update of your dials in the

options in the main menu.

That's cool! Ok great, glad it is part of this and intended to be there. Need to confirm it is not a bug or someone tampering with an add-on since I use it at work.

Thank you for clarifying!

+1

You're welcome! It's not a but. These windows are part of process when dials refreshing or getting their preview images. With new Firefox 57+ it works this way.

Sounds good, thank you again for the answer! :)