A workaround fix for Issue 3693....

chrome/browser/renderer_host/render_widget_host_view_win.cc

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/renderer_host/render_widget_host_view_win.h"
 
 #include "base/command_line.h"
 #include "base/gfx/gdi_util.h"
 #include "base/gfx/rect.h"
 #include "base/histogram.h"
@@ skipping 792 matching lines @@
       case WM_MOUSEMOVE:
       case WM_MOUSELEAVE:
       case WM_RBUTTONDOWN: {
         // Give the WebContents first crack at the message. It may want to
         // prevent forwarding to the renderer if some higher level browser
         // functionality is invoked.
         if (SendMessage(GetParent(), message, wparam, lparam) != 0)
           return 1;
       }
     }
+
+    // WebKit does not update its IME status when a user clicks a mouse button
+    // to change the input focus onto a popup menu. As a workaround, we finish
+    // an ongoing composition every time when we click a left button.
+    if (message == WM_LBUTTONDOWN)
+      ime_input_.CleanupComposition(m_hWnd);
   }
 
   ForwardMouseEventToRenderer(message, wparam, lparam);
   return 0;
 }
 
 LRESULT RenderWidgetHostViewWin::OnKeyEvent(UINT message, WPARAM wparam,
                                             LPARAM lparam, BOOL& handled) {
   handled = TRUE;
 
@@ skipping 252 matching lines @@
     // WM_LBUTTONDOWN.
     SetFocus();
   }
 }
 
 void RenderWidgetHostViewWin::ShutdownHost() {
   shutdown_factory_.RevokeAll();
   render_widget_host_->Shutdown();
   // Do not touch any members at this point, |this| has been deleted.
 }