add: document.getElementById("key_toggleMessagePane").removeAttribute("disabled"); 
context: function ShowingThreadPane(){  var threadPaneSplitter = document.getElementById("threadpane-splitter");  threadPaneSplitter.collapsed = false;  GetMessagePane().collapsed = (threadPaneSplitter.getAttribute("state") == "collapsed");}
meta: 5872	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/5872/14ca93ed836416532855dfdd856a7558bc73562a/mailWindow.js/clean/mail/base/content/mailWindow.js