Comment 6 for bug 1296978

Unfortunately we will need to leave that Apply problem unsolved for 14.04. Choosing an appropriate UI scale is fundamentally different from choosing resolution and rotation. With resolution and rotation, if you get it wrong, you'll usually want to go back to completely to what you had before. So that confirmation dialog has, instead of a "Cancel" button, a "Restore Previous Configuration" button.

But with UI scale, if you get it wrong, it's usually because you got it nearly right. So you want to make a small adjustment to your previous attempt, not restart it from scratch. And we have neither time before 14.04, nor screen real estate, to implement a preview to replace the instant-apply setting. (We will have screen real estate once the Launcher settings are moved to a separate panel.)

Instead, we will try solving the problem in a subtle way. If you move the UI scale slider so much that the window resizes to push the slider off-screen, the System Settings window as a whole will move just enough so that the whole slider (or, in an extreme case, the slider thumb and as much as possible of the slider around it) appears on-screen again. That way, even if the rest of the window becomes inaccessible, you can undo your change and make the rest of the window accessible again.