Shuttleworth: Unity shell will be default desktop in Ubuntu 11.04 (ars technica) [LWN.net]

Shuttleworth: Unity shell will be default desktop in Ubuntu 11.04 (ars technica)

Posted Oct 26, 2010 19:58 UTC (Tue) by rgmoore (✭ supporter ✭, #75)
In reply to: Shuttleworth: Unity shell will be default desktop in Ubuntu 11.04 (ars technica) by Arker
Parent article: Shuttleworth: Unity shell will be default desktop in Ubuntu 11.04 (ars technica)

Global menus are great, I dont understand why anyone wouldnt want them.

Because they're no longer ergonomically optimal by Fitt's Law. According to Fitt's law, the time it takes to move to a different spot on the screen depends on D/W, where D is the distance to the spot and W is the effective size. Since global menus run to the very top of the screen, their vertical size is effectively infinite. So the vertical move to a global menu is faster than that to a window menu, which requires a degree of precision that slows the pointer movement down. (This is especially obvious when using a low precision pointing device like a track pad.) With a small screen, like the original Macs, people tended to keep their windows sized almost as big as the screen. The difference in travel distance to a window menu vs. a global menu was small, and it was generally faster to get the mouse to a global menu than to a window menu.

With larger modern monitors, that's often no longer true. The global menu is always on the upper left of the screen, making it inconvenient when using a window that's positioned far to the right. In that case, the shorter horizontal distance may make a window menu faster to use than a global menu. That's especially important because most modern monitors are wide format, so it's common to spread windows horizontally. Also, the vertical positioning advantage of a global menu only applies when moving from the window to the menu; the move back to the window is faster with a window menu than a global menu. Between those factors, global menus have lost most of their ergonomic advantages, which were the main thing they had going for them.

As a practical example, imagine a dual monitor set-up with the desktop spread across both monitors. If you position a window on the right monitor, you'll have to move your mouse all the way back to the left monitor to do use a global menu. I don't know about you, but that seems awkward enough that I'd rather go with window menus.

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