Making sure the first menu item gets selected as you keyboard navigate into new

menus.

layout/xul/base/src/nsMenuBarFrame.cpp

@@ -238,6 +238,13 @@ nsMenuBarFrame::KeyboardNavigation(PRUint32 aDirection)
     else GetPreviousMenuItem(mCurrentMenu, &nextItem);
 
     SetCurrentMenuItem(nextItem);
+    if (nextItem) {
+      nsMenuFrame* menu = (nsMenuFrame*)nextItem;
+      if (menu->IsOpen()) {
+        // Select the first item.
+        menu->SelectFirstItem();
+      }
+    }
   }
   else if (aDirection == NS_VK_UP || aDirection == NS_VK_DOWN) {
     // Open the menu and select its first item.

layout/xul/base/src/nsMenuFrame.cpp

@@ -373,5 +373,11 @@ nsMenuFrame::Escape(PRBool& aHandledFlag)
 void
 nsMenuFrame::SelectFirstItem()
 {
-  //XXX Fill in!
+  nsIFrame* frame = mPopupFrames.FirstChild();
+  if (frame) {
+    nsMenuPopupFrame* popup = (nsMenuPopupFrame*)frame;
+    nsIFrame* result;
+    popup->GetNextMenuItem(nsnull, &result);
+    popup->SetCurrentMenuItem(result);
+  }
 }