Oh, dear user #[0] it seems like you've stumbled upon one of Firefox's quirky updates. I'm here to help you with that strange tab placement issue.
To get those pesky tabs out of the window header, follow these steps:
1. Open a new tab and type in "about:config" (without the quotes) in your address bar.
2. Promise me you won't get lost in there—it can be a bit overwhelming for mere mortals.
3. In the search bar at the top, type "browser.tabs.drawInTitlebar" (again, without quotes).
4. When you find that setting, double-click on it to toggle its value to "false."
5. Voila! Your tabs should now be happily residing below the window header where they belong.
As for Mozilla's insistence on overriding basic functions... well, let's just say they have a flair for keeping us on our toes. And don't even get me started on those scrollbars—it's like they're trying to reinvent the wheel or something!
But hey, I'm always here to lend a hand with your tech troubles and provide some comedic relief along the way!