* doc/HELPER-PROTOCOL
   - Add im_switcher_start and im_switcher_quit to fix bug #2112.
 * helper/im-switcher-gtk.c
   - (parse_helper_str): Call parse_helper_str_im_switcher()
     to parse "im_switcher_{start,quit}".
   - (parse_helper_str_im_switcher): New function.
   - (main): Check if another uim-im-switcher exists by trying
     to contact one. If one exists, this process exits.
 * qt4/switcher/qt4.cpp
   - (UimImSwitcher::UimImSwitcher): Check if another uim-im-switcher exists
     by trying to contact one.
     If one exists, this process exits.
   - (UimImSwitcher::slotStdinActivated): Call parseHelperStrImSwitcher()
     to parse "im_switcher_{start,quit}".
   - (UimImSwitcher::parseHelperStrImSwitcher): New function.
 * qt4/switcher/qt4.h
   - (UimImSwitcher): Add parseHelperStrImSwitcher().

---
 doc/HELPER-PROTOCOL      |   23 ++++++++++++++++++++++-
 helper/im-switcher-gtk.c |   16 ++++++++++++++++
 qt4/switcher/qt4.cpp     |   13 +++++++++++++
 qt4/switcher/qt4.h       |    2 +-
 4 files changed, 52 insertions(+), 2 deletions(-)

diff --git a/doc/HELPER-PROTOCOL b/doc/HELPER-PROTOCOL
index 2787ce6..1d6ee8f 100644
--- a/doc/HELPER-PROTOCOL
+++ b/doc/HELPER-PROTOCOL
@@ -91,7 +91,9 @@ protocol within uim.
               im_change_this_application_only |
               prop_update_custom  |
               custom_reload_notify |
-              commit_string) "\n"
+              commit_string |
+              im_switcher_start |
+              im_switcher_quit) "\n"
 
   charset_specifier = "charset=" charset "\n"
   charset = "UTF-8" | "EUC-JP" | "GB18030" |
@@ -324,6 +326,25 @@ protocol within uim.
     commit_string = "commit_string\n" charset_specifier str_to_commit "\n"
     str_to_commit = /^[^\n]+$/
 
+  - im_switcher_start
+
+    This message notifies that a new uim-im-switcher is started.
+    When an existing old uim-im-switcher receives im_switcher_start,
+    the existing uim-im-switcher must send im_switcher_quit
+    to quit newly started uim-im-switcher.
+
+    See also im_switcher_quit.
+  
+    im_switcher_start = "im_switcher_start\n"
+
+  - im_switcher_quit
+
+    This message requests newly started uim-im-switcher to quit.
+    All uim-im-switcher must quit immediately after received this message.
+
+    See also im_switcher_start.
+  
+    im_switcher_quit = "im_switcher_quit\n"
 
 Local Variables:
 mode: indented-text
diff --git a/helper/im-switcher-gtk.c b/helper/im-switcher-gtk.c
index af09ae2..9bcd853 100644
--- a/helper/im-switcher-gtk.c
+++ b/helper/im-switcher-gtk.c
@@ -56,6 +56,8 @@ reload_im_list(GtkWindow *window, gpointer user_data);
 static void
 parse_helper_str(const char *sent_str);
 static void
+parse_helper_str_im_switcher(const char *im_switcher_str_new);
+static void
 parse_helper_str_im_list(const char *im_list_str_new);
 static void
 check_helper_connection(void);
@@ -430,6 +432,8 @@ parse_helper_str(const char *sent_str)
 {
   if (g_str_has_prefix(sent_str, "im_list") == TRUE) {
     parse_helper_str_im_list(sent_str);
+  } else if (g_str_has_prefix(sent_str, "im_switcher_") == TRUE) {
+    parse_helper_str_im_switcher(sent_str);
   }
 }
 
@@ -443,6 +447,15 @@ get_text(const char *str)
 }
 
 static void
+parse_helper_str_im_switcher(const char *im_switcher_str_new)
+{
+  if (g_str_has_prefix(im_switcher_str_new, "im_switcher_start\n") == TRUE)
+    uim_helper_send_message(uim_fd, "im_switcher_quit\n"); 
+  else if (g_str_has_prefix(im_switcher_str_new, "im_switcher_quit\n") == TRUE)
+    gtk_main_quit();
+}
+
+static void
 parse_helper_str_im_list(const char *im_list_str_new)
 {
   gchar **lines;
@@ -556,6 +569,9 @@ main(int argc, char *argv[])
   uim_fd = -1;
   check_helper_connection();
 
+  /* to check if another uim-im-switcher exists */
+  uim_helper_send_message( uim_fd, "im_switcher_start\n" ); 
+
   /* To load input method list */
   uim_helper_send_message(uim_fd, "im_list_get\n");
 
diff --git a/qt4/switcher/qt4.cpp b/qt4/switcher/qt4.cpp
index f29b42a..3057ed7 100644
--- a/qt4/switcher/qt4.cpp
+++ b/qt4/switcher/qt4.cpp
@@ -85,6 +85,9 @@ UimImSwitcher::UimImSwitcher( QWidget *parent )
     uim_fd = -1;
     checkHelperConnection();
 
+    /* to check if another uim-im-switcher exists */
+    uim_helper_send_message( uim_fd, "im_switcher_start\n" );
+
     /* to load input method list */
     uim_helper_send_message( uim_fd, "im_list_get\n" );
 
@@ -244,6 +247,8 @@ void UimImSwitcher::slotStdinActivated()
             reloadImList();
         else if ( msg.startsWith( QLatin1String( "im_list" ) ) )
             parseHelperStrImList( msg );
+        else if ( msg.startsWith( QLatin1String( "im_switcher_" ) ) )
+            parseHelperStrImSwitcher( msg );
     }
 }
 
@@ -306,3 +311,11 @@ void UimImSwitcher::reloadImList()
     /* send request to get im list */
     uim_helper_send_message( uim_fd, "im_list_get\n" );
 }
+
+void UimImSwitcher::parseHelperStrImSwitcher( const QString &message )
+{
+    if ( message.startsWith( QLatin1String( "im_switcher_start\n" ) ) )
+        uim_helper_send_message( uim_fd,  "im_switcher_quit\n" );
+    else if ( message.startsWith( QLatin1String( "im_switcher_quit\n" ) ) )
+        QApplication::instance()->quit();
+}
diff --git a/qt4/switcher/qt4.h b/qt4/switcher/qt4.h
index 0a40703..8fd6bd6 100644
--- a/qt4/switcher/qt4.h
+++ b/qt4/switcher/qt4.h
@@ -62,8 +62,8 @@ protected:
     static void helper_disconnect_cb();
 
     void parseHelperStrImList( const QString &message );
-
     void reloadImList();
+    void parseHelperStrImSwitcher( const QString &message );
 
 protected slots:
     void slotStdinActivated();
-- 
1.6.4.2