ui/gtk3: Warn deprecated IBus XKB engines /w dialog

simple.xml is updated by IBus release and some XKB engines
could be deprecated with xkeyboard-config updates.
Now a warning dialog is launched when the deprecated engines are
changed to xkb:us::eng engine.

BUG=#2274

po/ibus10.pot

@@ -5,10 +5,10 @@
 #
 msgid ""
 msgstr ""
-"Project-Id-Version: ibus 1.5.22\n"
+"Project-Id-Version: ibus 1.5.23\n"
 "Report-Msgid-Bugs-To: https://github.com/ibus/ibus/issues\n"
-"POT-Creation-Date: 2020-09-03 21:21+0900\n"
-"PO-Revision-Date: 2020-09-03 21:21+0900\n"
+"POT-Creation-Date: 2020-11-21 07:09+0900\n"
+"PO-Revision-Date: 2020-11-21 07:09+0900\n"
 "Last-Translator: Takao Fujiwara <takao.fujiwara1@gmail.com>\n"
 "Language-Team: Source\n"
 "Language: \n"
@@ -402,7 +402,7 @@ msgstr ""
 msgid "More…"
 msgstr ""
 
-#: setup/engineabout.py:37 setup/setup.ui:1368 ui/gtk3/panel.vala:1162
+#: setup/engineabout.py:37 setup/setup.ui:1368 ui/gtk3/panel.vala:1176
 msgid "About"
 msgstr ""
 
@@ -3172,7 +3172,7 @@ msgid "Alias: %s"
 msgstr ""
 
 #: ui/gtk3/emojier.vala:2140 ui/gtk3/ibus-extension-gtk3.desktop.in:3
-#: ui/gtk3/ibus-ui-emojier.desktop.in:3 ui/gtk3/panel.vala:1147
+#: ui/gtk3/ibus-ui-emojier.desktop.in:3 ui/gtk3/panel.vala:1161
 msgid "Emoji Choice"
 msgstr ""
 
@@ -3233,23 +3233,31 @@ msgstr ""
 msgid "IBus Panel"
 msgstr ""
 
-#: ui/gtk3/panel.vala:1119
+#: ui/gtk3/panel.vala:970
+#, c-format
+msgid ""
+"Your input method %s does not exist in IBus input methods so \"US\" layout "
+"was configured instead of your input method. Please run `ibus-setup` "
+"command, open \"Input Method\" tab, and configure your input methods again."
+msgstr ""
+
+#: ui/gtk3/panel.vala:1133
 msgid "IBus is an intelligent input bus for Linux/Unix."
 msgstr ""
 
-#: ui/gtk3/panel.vala:1123
+#: ui/gtk3/panel.vala:1137
 msgid "translator-credits"
 msgstr ""
 
-#: ui/gtk3/panel.vala:1142
+#: ui/gtk3/panel.vala:1156
 msgid "Preferences"
 msgstr ""
 
-#: ui/gtk3/panel.vala:1168
+#: ui/gtk3/panel.vala:1182
 msgid "Restart"
 msgstr ""
 
-#: ui/gtk3/panel.vala:1172
+#: ui/gtk3/panel.vala:1186
 msgid "Quit"
 msgstr ""
 

ui/gtk3/panel.vala

@@ -970,6 +970,21 @@ class Panel : IBus.PanelService {
             names =  {"xkb:us::eng"};
             m_settings_general.set_strv("preload-engines", names);
             engines = m_bus.get_engines_by_names(names);
+            var message = _("Your input method %s does not exist in IBus " +
+                    "input methods so \"US\" layout was configured instead " +
+                    "of your input method. Please run `ibus-setup` command, " +
+                    "open \"Input Method\" tab, and configure your input " +
+                    "methods again.").printf(names[0]);
+            var dialog = new Gtk.MessageDialog(
+                    null,
+                    Gtk.DialogFlags.DESTROY_WITH_PARENT,
+                    Gtk.MessageType.WARNING,
+                    Gtk.ButtonsType.CLOSE,
+                    message);
+            dialog.response.connect((id) => {
+                    dialog.destroy();
+            });
+            dialog.show();
 	}
 
         if (m_engines.length == 0) {