Same thing with, e.g., firefox on ubuntu. Not only do you have to hunt for free space, but because of visual design (in turn because of vanity and frivolity, IMO) it's not clear where it is until you mouse over it and display its highlighted color. The "close" button barely even changes color on the default theme, so god forbid you single-click it. And tabs can accidentally be dragged, rather than just failing to drag the entire window.
This next part is more of a funny absurd story than a complaint, but I once had a recurring bug where the browser UI was shifted down a hundred or so pixels from the top of the window, replaced by some flat "blank" color. But the interactions were still taking place in their expected areas. So in order to fix that, I had to hunt around with my mouse at the top of the window, look for UI elements to become highlighted in the middle of the window, and then move left or right until I was confident I was over the title bar (which I couldn't know for sure, since it itself doesn't highlight).
This next part is more of a funny absurd story than a complaint, but I once had a recurring bug where the browser UI was shifted down a hundred or so pixels from the top of the window, replaced by some flat "blank" color. But the interactions were still taking place in their expected areas. So in order to fix that, I had to hunt around with my mouse at the top of the window, look for UI elements to become highlighted in the middle of the window, and then move left or right until I was confident I was over the title bar (which I couldn't know for sure, since it itself doesn't highlight).