diff --git a/src/calibre/gui2/preferences/search.py b/src/calibre/gui2/preferences/search.py
index 5f4d7d94f9..7795844081 100644
--- a/src/calibre/gui2/preferences/search.py
+++ b/src/calibre/gui2/preferences/search.py
@@ -234,6 +234,7 @@ class ConfigWidget(ConfigWidgetBase, Ui_Form):
                 'The option to have un-accented characters match accented characters has no effect'
                 ' if you also turn on case-sensitive searching. So only turn on one of those options'), show=True)
             raise AbortCommit()
+        restart = ConfigWidgetBase.commit(self)
         if self.gst_changed:
             self.db.new_api.set_pref('grouped_search_terms', self.gst)
             self.db.field_metadata.add_grouped_search_terms(self.gst)
@@ -252,7 +253,7 @@ class ConfigWidget(ConfigWidgetBase, Ui_Form):
         else:
             cats.discard('search')
         self.db.new_api.set_pref('categories_using_hierarchy', list(cats))
-        return ConfigWidgetBase.commit(self)
+        return restart
 
     def refresh_gui(self, gui):
         gui.refresh_search_bar_widgets()
@@ -260,8 +261,8 @@ class ConfigWidget(ConfigWidgetBase, Ui_Form):
         gui.current_db.new_api.clear_caches()
         set_use_primary_find_in_search(prefs['use_primary_find_in_search'])
         gui.set_highlight_only_button_icon()
-        if self.muc_changed:
-            gui.tags_view.recount()
+        if self.gst_changed or self.muc_changed:
+            gui.tags_view.model().reset_tag_browser()
         gui.search.search_as_you_type(config['search_as_you_type'])
         gui.search.do_search()
 
diff --git a/src/calibre/gui2/tag_browser/view.py b/src/calibre/gui2/tag_browser/view.py
index a07c3ab671..b3b88bb36a 100644
--- a/src/calibre/gui2/tag_browser/view.py
+++ b/src/calibre/gui2/tag_browser/view.py
@@ -715,6 +715,7 @@ class TagsView(QTreeView):  # {{{
         index = self.indexAt(point)
         self.context_menu = QMenu(self)
         added_show_hidden_categories = False
+        key = None
 
         def add_show_hidden_categories():
             nonlocal added_show_hidden_categories
@@ -1046,7 +1047,7 @@ class TagsView(QTreeView):  # {{{
 
         # partioning. If partitioning is active, provide a way to turn it on or
         # off for this category.
-        if gprefs['tags_browser_partition_method'] != 'disable':
+        if gprefs['tags_browser_partition_method'] != 'disable' and key is not None:
             m = self.context_menu
             p = self.db.prefs.get('tag_browser_dont_collapse', gprefs['tag_browser_dont_collapse'])
             if key in p: