With a maximized window, the back button should be click-able from the extreme left edge of the screen, next to the button. This is to take advantage of Fitts's law.
Bug 571454 fixed this issue for large icons but did not fix it for small icons.
Created attachment 545515 [details] [diff] [review]
Patch for bug 670565
I have a different fix for this in bug 671553.