Version 3.7 is a Disaster Rated 2 out of 5 stars
This latest version completely trashed my Firefox 188.8.131.52 install.
It wrecked my theme (Winestripe) changing the colour of inactive tabs as well as the tab background and removing some of my visual customisations (which made the theme look really ugly). It also totally ruined all my neatly customised context menu items (which I had changed using CustomizeMenu). Instead I got pretty much every context menu choice available visible all at one in the context menu (and in a totally random order).
This makes it a truly horrible experience using Firefox (because you it takes ages to find the menu option that you want). Disabling TabMix Plus v3.7 removes the theme problems, but the menu problems remain.
Fortunately I had a backup, so I had to export all my bookmarks, adblock and noscript settings and then restore the old backup and everything was back as it should be.
This release can't have been tested at all, because it's a total disaster.
After 3.7 was installed