There is empty space ABOVE the tabs, half a mm or so that takes away from the reading space, but the problem it causes is that you can't just slam your mouse to the top of the screen to click the tab, you need to go away from the redundant space to click a tab. That is a design mistake, not a choice. Tabs at the top is what everyone does, and that's correct. How you've done it is a mistake.
Not feeling like what I wrote was actually read.
There is empty space ABOVE the tabs, half a mm or so that takes away from the reading space, but the problem it causes is that you can't just slam your mouse to the top of the screen to click the tab, you need to go away from the redundant space to click a tab. That is a design mistake, not a choice. Tabs at the top is what everyone does, and that's correct. How you've done it is a mistake.