I have noticed that in order to have a screen maximized within the viewport without actually entering "full screen/no distractions" mode in Yosemite, I only need to hold the Option key and left-click the maximize button, and that's worked for everything I use on a daily basis: Finder, Chrome, Transmit, SublimeText 3, WebStorm, Outlook, iTerm 2, and even Photoshop CS5(which seems to give me some issues with sizing on my Mac). I don't think you need to hold the Shift key to achieve the screen maximization you're looking for!