Linked by Thom Holwerda on Thu 17th May 2007 18:54 UTC
Gnome In the GNOME bugzilla, there is an ongoing discussion about whether or not to include a patch into the default GNOME installation which would enable GNOME to (optionally) have a global application menubar, similar to that of the Mac OS and KDE (in the latter it is optional and off by default). Installation instructions and .deb packages, as well as a 60-page (and counting) discussion of the patch, are available on the UbuntuForums. Read on for a poll on this issue.
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Some numbers
by rayiner on Thu 17th May 2007 20:00 UTC
rayiner
Member since:
2005-07-06

It's interesting to put some numbers to Fitt's law:

T = a + b log2(D/W + 1)

We consider two cases: menubar at the top, and menubar in the window, both on my MacBook (1280x800 screen). In both cases, we'll assume we're trying to hit the menubar from a resting position in the center of the screen. We'll simplify the math by considering vertical motion only.

Consider the first case, with the menubar at the top. In this case, D = ~400 pixels. W is not infinity, but a number bounded by the maximal overshoot that would occur using the quick mouse movement used to reach the menubar. In my experiments, if I move the mouse with the same motion I use to hit the menubar, I can get within about 50 pixels on either side of the target. This means that W for this case = ~100 pixels.

Now, consider the second case, with the menubar in the window. Of the several dozen Windows I have open right now, all of them are within about 200 pixels of the top of the screen. Thus, D = ~200 pixels. W is the height of the menu bar itself, which is 20 pixels (OS X uses particularly large menubar text --- the number for GNOME would be even smaller).

Now, for the first case, we have:

D / W = ~4

And in the second case, we have:

D / W = ~10

So, even though the distance to the target doubled, the overall ratio is still better because the effective width of the menubar increased by a factor of five.

There are some arguments on the other side, but none are particularly convincing. Yes, if you're trying to activate a menu entry on a window that doesn't have focus, there is some extra motion involved with the toplevel menubar. However, that argument is mitigated by two factors: first, IIRC, GNOME discards the focusing click, so you can't click directly on the menubar of an unfocused window anyway. Second, the toplevel menubar is usually designed to be a per-application menubar, not a per-window menubar. While it may be fairly common to want to click on the menubar of an unfocused window in the same app, it's probably much less common to want to click on the menubar of an unfocused window in an entirely different application.

Also, while larger monitors might increase the D term in the above equation, it doesn't increase by much. My 20" monitor on my desk has a height of only 1050 pixels, and the 24" one I had before that only had a height of 1200 pixels. If you run the numbers, you can see that the change in D still doesn't offset the change in W. Moreover, the popularity of laptops (and the attendant poor pointing devices therein) further works against that particular argument.

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