rem: var previousMessage = GetPreviousMessage(selArray[0], previousFunction, startFromEnd); ChangeSelection(tree, previousMessage); 
add: var currentMessage = selArray[0]; var previousMessage = GetPreviousMessage(currentMessage, previousFunction, startFromEnd);  if(previousMessage && (previousMessage != currentMessage)) ChangeSelection(tree, previousMessage); 
context: function GoPreviousMessage(previousFunction, startFromEnd){	var tree = GetThreadTree();		var selArray = tree.selectedItems;	if ( selArray && (selArray.length == 1) )	{		var previousMessage = GetPreviousMessage(selArray[0], previousFunction, startFromEnd);		ChangeSelection(tree, previousMessage);	}}
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/aa5e2f67eae16c5c9d8f1c4985ac6f9e152696a3/msgViewNavigation.js/clean/mailnews/base/resources/content/msgViewNavigation.js