Does Firefox 90 fully respect the default desktop theme and show tab divider lines?
When version 89.2 rolled out, I was highly displeased by the fact that the default theme now no longer properly reflected the Windows theme settings (extremely noticeable on my end, since I use the Windows Classic theme with customized "3D object" colors); this defect had already affected the options dropdown but had now spread to the address/navigation bar, bookmarks toolbar, and scrollbar. This was extremely annoying, especially since none of the add-on themes can properly duplicate that aesthetic function. One of the things I liked about Firefox was that unlike Chrome, Opera, and Edge... it actually still respected the Windows theme settings (which programs like browsers should do by default). And now, that prized trait had been inexplicably and insensibly discarded.
I was further displeased by the removal of the dividing lines between tabs. This made Firefox substantially harder for me to use, almost headache-inducingly so. Whoever you have testing these changes before rollout - if anyone - should be replaced, because this was a massive accessibility downgrade. Unacceptably so.
These changes were so frustrating and ugly, and made the browser so much more difficult for me to use, that I reverted to version 88 and continue to remain on that version.
Does version 90 resolve these issues? If it does, I'll update. But if not.... then in my opinion it should be axed and you should cease pushing it in favor of working on a new version that does fix these poor decisions. And I'll be sticking to version 88 until that happens.