+1  A: 

The labels left and right are avoided because left-handed people will have the buttons reversed. What does it mean when a lefty mouse has its right button clicked? Should the program perform its right-click action or its left-click action. If we simply swap the mappings, then right and left become rather meaningless to the programmer.

I assume the designers of Squeak wanted to avoid this thorny issue, so actions are labeled with colors which are agnostic to right/left.

Greg
+2  A: 

Squeak is a SmallTalk tool. Obviously they feel compelled to abstract the buttons into something less specific.

It appears they've blurred the line between reality and code constructs.

phord
+6  A: 

The button colors probably date back to the experiments at Xerox (where the mouse was invented). So maybe the question should be “why do current computers have colorless mouse buttons?” :D

As for sticking with the colors in the book, I think the reason was that the colors are still mentioned in the code, and colors don't always get mapped to the same fingers depending on the platform. But I agree, the color system is not very practical; probably the best would be to use primary/secondary/tertiary buttons?

Damien Pollet
A: 

There is no rational reason for this - for some reasom Smalltalkers seem impelled to throw up barriers to acceptance of the language whenever possible.

Having said that, if you sit down and use the Squeak IDE for a an hour or so, your fingers will soon learn which bitton to press. And once you get used to it (and have customised it so that you can actually read the menus etc.) the IDE is quite fun. I like playing with Morphic, for example.

anon
+4  A: 

That's one of those things you take with a grain of salt. :) I read that the other day, and I will certainly not go out of my way to add some colourful buttons to my mouse.

Just mentally substitute "left-click" for red, etc.

Jeramy Rutley
+4  A: 

It's ridiculous. Left and right are already abstract concepts. Naming the buttons with colours is an abstraction of an abstraction.

Well, colors were very concrete on the original mice for the Xerox Alto, it's just a standard that didn't live.
Damien Pollet
No, Left and Right are not "already abstract concepts". Where does that come from?We call the Left mouse button such because it actually *is* in the left. Left handed people still get confused by this --which goes to show that it is not an abstract concept.
foljs
+1  A: 

This legacy is so 70ies, I hope that Pharo will fix this.

Adrian
+1  A: 

Contrary to what Damien said, the mouse was not invented at Xerox; rather, it was invented by team at Stanford Research Institute led by Douglas Engelbart as part of their revolutionary ONLINE system.

The coloring of the buttons is an old, old convention, one that I personally tend not to pay much attention to. The odd thing about that image you posted, though, is that the right button ("yellow" in Smalltalk parlance) appears more green than yellow--at least, to me. Does it appear that way to anyone else? Perhaps this is in part why the coloring convention was dropped elsewhere (and ought similarly be abandoned in Squeak).

Germans were first: http://www.heise.de/newsticker/Auf-den-Spuren-der-deutschen-Computermaus--/meldung/136901
stesch
+1  A: 

The paragraph that was quoted has been echoed among the answers as well: the "left-click" might or might not come from the button on the left - and the "right-click" might or might not come from the button on the right.

A pet peeve of mine is the talk of a "third button" - which almost always is in the middle. The sequence is not 1-3-2 but 1-2-3. Perhaps that third button should be a color too....

David