title: Why is there no multipleDefine error in a layer file?
body: <p>Reading much about module loading, I learned, that a module has to be defined in a single JavaScript file.
  This rule is broken in the dojo layer file (<a href="http://download.dojotoolkit.org/release-1.9.0/dojo.js.uncompressed.js" rel="nofollow">http://download.dojotoolkit.org/release-1.9.0/dojo.js.uncompressed.js</a>). 
  I thought that the file name is part of the module identifier, so I do not understand how the modules are resolved in this layer file and why there is no "multipleDefine" error ;-)</p>