I've taken a screenshot using both Ubuntu's built-in screenshot utility and the Shutter utility, and both of them are getting the colors wrong. I've taken a screenshot of the original and the screenshots side by side by side to show how much they're off.
The one on the left is the original, created with OpenGL. The one on the top right is the one taken by Shutter. The one on the bottom right is the one taken by Ubuntu's default screenshot tool (the black scribbles on the window header is where I've scribbled out the file name). Although it seems to me that Shutter did slightly better than the default tool, it's still quite a bit off. I've viewed this screenshot on two different monitors and the difference is relatively apparent on both.
Could this be an issue with my computer's graphics or might this be a problem with Ubuntu/Linux itself?
I'm running Ubuntu 16.10.