FireFox order of windows changes after reboot

[JDD]

Hi!

My system:

Acer VERITON MN: VM4630G-i7477X
32GB Ram
256GB SSD program drive
1-TB HDD data drive
Win7Pro 64-bit with Taskbar configuration manager "7+TaskbarTweaker"
FireFox v 56.0.2 (64-bit) with FireFox extension "TabMixPlus"

Problem:

I normally keep five (5) FireFox windows open with a total of 43 tabs between them.

Each window can have from 4 to 20 tabs.

Whenever I shutdown, reboot & restart FireFox the order of the windows shown
in the Taskbar is never the same.

Prior to shutting down I have ordered the FF windows the way I want them, but
upon rebooting and restarting FF the windows are never in the same order.

What to do?

Is there a setting I've missed?

Thanks for any advice!

 

[TrainableMan]

This is not a Windows OS issue, Firefox is browser software so I moved it to the Software thread.

Your issue is specific to Firefox so you may not get a lot of responses on a Win7 forum. You would likely do better on a Forum dedicated to Firefox. Try Mozilla.com as they are the authors of Firefox