Mouse press should focus on any types of form controls.

Source/core/page/EventHandler.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2012 Digia Plc. and/or its subsidiary(-ies)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 2027 matching lines @@
         }
 
         // Only change the focus when clicking scrollbars if it can transfered to a mouse focusable node.
         if ((!node || !node->isMouseFocusable()) && isInsideScrollbar(mouseEvent.position()))
             return false;
 
         // If focus shift is blocked, we eat the event.  Note we should never clear swallowEvent
         // if the page already set it (e.g., by canceling default behavior).
         if (Page* page = m_frame->page()) {
             if (node && node->isMouseFocusable()) {
-                if (!page->focusController()->setFocusedNode(node, m_frame))
+                if (!page->focusController()->setFocusedNode(node, m_frame, FocusDirectionMouse))
                     swallowEvent = true;
             } else if (!node || !node->focused()) {
                 if (!page->focusController()->setFocusedNode(0, m_frame))
                     swallowEvent = true;
             }
         }
     }
 
     return !swallowEvent;
 }
@@ skipping 980 matching lines @@
         return;
 
     bool isOptioned = event->getModifierState("Alt");
     bool isCommanded = event->getModifierState("Meta");
 
     SelectionDirection direction = DirectionForward;
     TextGranularity granularity = CharacterGranularity;
 
     switch (focusDirectionForKey(event->keyIdentifier())) {
     case FocusDirectionNone:
+    case FocusDirectionMouse:
         return;
     case FocusDirectionForward:
     case FocusDirectionBackward:
         ASSERT_NOT_REACHED();
         return;
     case FocusDirectionUp:
         direction = DirectionBackward;
         granularity = isCommanded ? DocumentBoundary : LineGranularity;
         break;
     case FocusDirectionDown:
@@ skipping 803 matching lines @@
 unsigned EventHandler::accessKeyModifiers()
 {
 #if OS(DARWIN)
     return PlatformEvent::CtrlKey | PlatformEvent::AltKey;
 #else
     return PlatformEvent::AltKey;
 #endif
 }
 
 } // namespace WebCore