I just checked Eclipse: Green circle with a white, right-pointing triangle. Then I checked Netbeans: Green right-pointing triangle. Both of these are unmistakable icons for 'play'. Edit: I even googled for screenshots of Visual Studio...green right-facing triangle.

http://en.wikipedia.org/wiki/File:Vs2010rtm.png

Could there be a more universal idiom in the world of IDEs?

What kind of button would you want to press?

really, cause that's exactly what button I look for when I'm in an IDE trying to figure out how to run a project. I'm sitting here looking at intellij which has a 'play' button for running code.

Guys, try reading his post: "When I want to build my project I do not want to press a play button."

He said BUILD, not RUN. A Play button is to build and RUN the project. I agree with his objection: There's no Build button in the UI.

And even worse is the width of the combined drop-down list for configurations. There's a vast expanse of empty space in the (now non-customizable) toolbar, and they made this control SMALLER. The information it should be providing is cut off in all cases, even with short project names. I try to be sympathetic to the Xcode team's tasks, but this is idiotic.

Me thinks you haven't been programming long if you don't know what the green triangle does. It's been a "play button" for over a decade.