I'm learning C, so I'm trying to figure out which editor I prefer—Vim or Emacs. Great way to start a holy war, I know. 
With Emacs, I'm a bit annoyed with one thing. It looks a bit weird with Mate, for some reason, in ways that aren't really a problem but are still annoying. For instance, the toolbar at the top doesn't line up right with the edge of the window. It depends on what theme I'm using (right now I'm using Ambient-Mate).
Like this. Again, not a huge issue, but it annoys me. I tried changing to Green-Submarine. The gap is gone, but now the background is greenish-blue instead of white:
Why should changing themes change the color of the background of my doc? Huh.
It just feels like Emacs is behaving strangely with the Mate themes, and it's distracting. Got any ideas of how to fix this? I'm thinking of building the latest version of Emacs on my laptop because the one in the repository is old anyway. Might this help?
EDIT: Just found this answer explaining the toolbar gap. Now that I know why it works that way, it's easier to ignore. 
I might just disable the toolbar. I still don't know why Green Submarine made my document blue-greenish, though.