Why doesn't the Windows 7 Start menu have a pushpin for pinning items?
You may have noticed a minor inconsistency between pinning a program to the Start menu and pinning a destination to a program’s Jump List. Although pinned items appear at the top of the respective lists, and both the Start menu and Jump List let you right-click an item and select Pin/Unpin, the Jump List also lets you pin and unpin an item by clicking on the pushpin. Why doesn’t the Start menu have a pushpin in addition to the right-click menu? For a time, items on the Start menu did have a pushpin, just like items on Jump Lists. The design had a few problems, however. Start menu items can also have a triangle indicating the presence of a flyout menu, and the presence of two indicators next to an item made the interface look awkward and too busy. And what do you do if an item has only one indicator? Do you right-justify all the indicators? Or do you place the indicators in columns and reserve blank space for the missing ones?
Both look ugly for different reasons. The right-justify-everything version looks ugly because the pushpin appears to keep moving around. The blank-space-if-no-flyout version looks ugly because you have a pushpin hovering in the middle of nowhere. (Imagine trying to click on one of these things: You just have to “know” that the magic click spot for pinning an item is 20 pixels to the left of the far right edge.) But the real death blow to showing a pushpin for pinning items to the Start menu was the usability testing. Users had trouble figuring out where to click to pin an item or to open the Jump List and frequently got the opposite of what they wanted. Since opening the Jump List is by far the more common operation, it won the battle of the prominent UI affordance, and the option for pinning and unpinning was left to a context menu.
Which, as it happens, is where the pin/unpin option started in the first place.