add: if (aCommand == "cmdEditCopy") { return this.mTree.view.selection.count > 0; } 
context:   isCommandEnabled: function(aCommand)  {    return false;  },
meta: 5459	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/5459/e997bb58841aae61443134d5c143e372b0ba7d72/computedStyle.js/buggy/extensions/inspector/resources/content/viewers/computedStyle/computedStyle.js