fixing bug 130982 - delete/move context menu command attempts to restore focus to invalid row. r=bhuvan sr=sspitzer

mailnews/base/resources/content/mailContextMenus.js

@@ -34,6 +34,8 @@ function RestoreSelectionWithoutContentLoad(outliner)
     var outlinerBoxObj = outliner.outlinerBoxObject;
     var outlinerSelection = outlinerBoxObj.selection;
 
+    // make sure that currentIndex is valid so that we don't try to restore
+    // a selection of an invalid row.
     if((!outlinerSelection.isSelected(outlinerSelection.currentIndex)) &&
        (outlinerSelection.currentIndex >= 0))
     {

mailnews/base/resources/content/msgMail3PaneWindow.js

@@ -900,6 +900,8 @@ function ChangeSelectionWithoutContentLoad(event, outliner)
     var outlinerSelection = outlinerBoxObj.selection;
 
     outlinerBoxObj.getCellAt(event.clientX, event.clientY, row, col, elt);
+    // make sure that row.value is valid so that it doesn't mess up
+    // the call to ensureRowIsVisible().
     if((row.value >= 0) && !outlinerSelection.isSelected(row.value))
     {
         var saveCurrentIndex = outlinerSelection.currentIndex;

mailnews/base/resources/content/threadPane.js

@@ -305,6 +305,9 @@ function GetThreadPaneFolder()
 
 function EnsureRowInThreadOutlinerIsVisible(index)
 {
+  if (index < 0)
+    return;
+
   var outliner = GetThreadOutliner();
   outliner.boxObject.QueryInterface(Components.interfaces.nsIOutlinerBoxObject).ensureRowIsVisible(index); 
 }