Two things:

1) Fixes for the icon clicks. It now works when items are painted out of order. Resizing is now accounted for.  Toggling and setting item focus now works properly.
2) Added items to the tag browser config menu, including the possibility of shortcuts.

src/calibre/gui2/tag_browser/ui.py

@@ -779,12 +779,26 @@ class TagBrowserWidget(QFrame):  # {{{
                 _('Configure Tag browser'), default_keys=(),
                 action=ac, group=_('Tag browser'))
         ac.triggered.connect(l.showMenu)
-
         l.m.aboutToShow.connect(self.about_to_show_configure_menu)
+        # Show/hide counts
         l.m.show_counts_action = ac = l.m.addAction('counts')
         ac.triggered.connect(self.toggle_counts)
+        # Show/hide average rating
         l.m.show_avg_rating_action = ac = l.m.addAction(QIcon.ic('rating.png'), 'avg rating')
         ac.triggered.connect(self.toggle_avg_rating)
+        # Show/hide notes icon
+        l.m.show_notes_icon_action = ac = l.m.addAction(QIcon.ic('notes.png'), 'notes icon')
+        ac.triggered.connect(self.toggle_notes_icon)
+        parent.keyboard.register_shortcut('tag browser toggle notes',
+                _('Toggle notes icons'), default_keys=(),
+                action=ac, group=_('Tag browser'))
+        # Show/hide links icon
+        l.m.show_links_icon_action = ac = l.m.addAction(QIcon.ic('external-link.png'), 'links icon')
+        ac.triggered.connect(self.toggle_links_icon)
+        parent.keyboard.register_shortcut('tag browser toggle links',
+                _('Toggle links icons'), default_keys=(),
+                action=ac, group=_('Tag browser'))
+
         sb = l.m.addAction(QIcon.ic('sort.png'), _('Sort by'))
         sb.m = l.sort_menu = QMenu(l.m)
         sb.setMenu(sb.m)
@@ -858,6 +872,12 @@ class TagBrowserWidget(QFrame):  # {{{
         ac = self.alter_tb.m.show_avg_rating_action
         ac.setText(_('Hide average rating') if config['show_avg_rating'] else _('Show average rating'))
         ac.setIcon(QIcon.ic('minus.png' if config['show_avg_rating'] else 'plus.png'))
+        ac = self.alter_tb.m.show_notes_icon_action
+        ac.setText(_('Hide notes icon') if gprefs['show_notes_in_tag_brouser'] else _('Show notes icon'))
+        ac.setIcon(QIcon.ic('minus.png' if gprefs['show_notes_in_tag_brouser'] else 'plus.png'))
+        ac = self.alter_tb.m.show_links_icon_action
+        ac.setText(_('Hide links icon') if gprefs['show_links_in_tag_brouser'] else _('Show links icon'))
+        ac.setIcon(QIcon.ic('minus.png' if gprefs['show_links_in_tag_brouser'] else 'plus.png'))
 
     def filter_book_list(self):
         self.tags_view.model().set_in_tag_browser()
@@ -865,9 +885,19 @@ class TagBrowserWidget(QFrame):  # {{{
 
     def toggle_counts(self):
         gprefs['tag_browser_show_counts'] ^= True
+        self.tags_view.recount_with_position_based_index()
 
     def toggle_avg_rating(self):
         config['show_avg_rating'] ^= True
+        self.tags_view.recount_with_position_based_index()
+
+    def toggle_notes_icon(self):
+        gprefs['show_notes_in_tag_brouser'] ^= True
+        self.tags_view.recount_with_position_based_index()
+
+    def toggle_links_icon(self):
+        gprefs['show_links_in_tag_brouser'] ^= True
+        self.tags_view.recount_with_position_based_index()
 
     def save_state(self):
         gprefs.set('tag browser search box visible', self.toggle_search_button.isChecked())

src/calibre/gui2/tag_browser/view.py

@@ -8,6 +8,7 @@ __docformat__ = 'restructuredtext en'
 import os
 import re
 import traceback
+from collections import defaultdict
 from contextlib import suppress
 from functools import partial
 from qt.core import (
@@ -95,22 +96,22 @@ class TagDelegate(QStyledItemDelegate):  # {{{
         if item.type == TagTreeItem.TAG:
             category = item.tag.category
             name = item.tag.original_name
-            m = self.tags_view._model
+            tv = self.tags_view
-            if show_notes and m.category_has_notes(category):
+            m = tv._model
-                icon = self.notes_icon if m.item_has_note(category, name) else self.blank_icon
-                width = int(tr.height()/2)
-                r = QRect(tr)
-                r.setRight(r.right() - 1), r.setLeft(r.right() - width - 4)
-                self.tags_view.current_note_button_position = (r.left(), r.left()+r.width())
-                icon.paint(painter, r, option.decorationAlignment, QIcon.Mode.Normal, QIcon.State.On)
-                tr.setRight(r.left() - 1)
-
             if show_links and m.category_has_links(category):
                 icon = self.links_icon if m.item_has_link(category, name) else self.blank_icon
                 width = int(tr.height()/2)
                 r = QRect(tr)
                 r.setRight(r.right() - 1), r.setLeft(r.right() - width - 4)
-                self.tags_view.current_link_button_position = (r.left(), r.left()+r.width())
+                tv.category_button_positions[category]['links'] = (r.left(), r.left()+r.width())
+                icon.paint(painter, r, option.decorationAlignment, QIcon.Mode.Normal, QIcon.State.On)
+                tr.setRight(r.left() - 1)
+            if show_notes and m.category_has_notes(category):
+                icon = self.notes_icon if m.item_has_note(category, name) else self.blank_icon
+                width = int(tr.height()/2)
+                r = QRect(tr)
+                r.setRight(r.right() - 1), r.setLeft(r.right() - width - 4)
+                tv.category_button_positions[category]['notes'] = (r.left(), r.left()+r.width())
                 icon.paint(painter, r, option.decorationAlignment, QIcon.Mode.Normal, QIcon.State.On)
                 tr.setRight(r.left() - 1)
         if not is_search and (hover or gprefs['tag_browser_show_counts']):
@@ -229,8 +230,6 @@ class TagsView(QTreeView):  # {{{
         self.setTabKeyNavigation(True)
         self.setAnimated(True)
         self.setHeaderHidden(True)
-        self.current_note_button_position = (-1, -1)
-        self.current_link_button_position = (-1, -1)
         self.setItemDelegate(TagDelegate(tags_view=self))
         self.made_connections = False
         self.setAcceptDrops(True)
@@ -248,6 +247,12 @@ class TagsView(QTreeView):  # {{{
         self.plus_icon = QIcon.ic('plus.png')
         self.minus_icon = QIcon.ic('minus.png')
 
+        # Dict for recording the positions of the fake buttons for category tag
+        # lines. It is recorded per category because we can't guarantee the
+        # order that items are painted. The numbers get updated whenever an item
+        # is painted, which deals with resizing.
+        self.category_button_positions = defaultdict(dict)
+
         self._model = TagsModel(self)
         self._model.search_item_renamed.connect(self.search_item_renamed)
         self._model.refresh_required.connect(self.refresh_required,
@@ -361,7 +366,7 @@ class TagsView(QTreeView):  # {{{
             match_pop = 0
         self.alter_tb.match_menu.actions()[match_pop].setChecked(True)
         if not self.made_connections:
-            self.clicked.connect(self.toggle)
+            self.clicked.connect(self.toggle_on_mouse_click)
             self.customContextMenuRequested.connect(self.show_context_menu)
             self.refresh_required.connect(self.recount, type=Qt.ConnectionType.QueuedConnection)
             self.alter_tb.sort_menu.triggered.connect(self.sort_changed)
@@ -457,29 +462,12 @@ class TagsView(QTreeView):  # {{{
         except:
             pass
 
-    def number_in_range(self, val, range_tuple):
-        return range_tuple[0] <= val <= range_tuple[1]
-
     def mousePressEvent(self, event):
         if event.buttons() & Qt.MouseButton.LeftButton:
+            # Record the press point for processing during the clicked signal
+            self.mouse_clicked_point = event.pos()
             # Only remember a possible drag start if the item is drag enabled
             dex = self.indexAt(event.pos())
-            t = self._model.data(dex, Qt.UserRole)
-            if t.type == TagTreeItem.TAG:
-                db = self._model.db.new_api
-                tag = t.tag
-                x = event.pos().x()
-                if self.number_in_range(x, self.current_note_button_position):
-                    from calibre.gui2.dialogs.show_category_note import ShowNoteDialog
-                    item_id = db.get_item_id(tag.category, tag.original_name)
-                    if db.notes_for(tag.category, item_id):
-                        ShowNoteDialog(tag.category, item_id, db, parent=self).show()
-                        return
-                elif self.number_in_range(x, self.current_link_button_position):
-                    link = db.get_link_map(tag.category).get(tag.original_name)
-                    if link:
-                        safe_open_url(link)
-                        return
             if self._model.flags(dex) & Qt.ItemFlag.ItemIsDragEnabled:
                 self.possible_drag_start = event.pos()
             else:
@@ -534,11 +522,37 @@ class TagsView(QTreeView):  # {{{
         joiner = ' and ' if self.match_all else ' or '
         return joiner.join(tokens)
 
+    def click_in_button_range(self, val, category, kind):
+        range_tuple = self.category_button_positions[category].get(kind)
+        return range_tuple and range_tuple[0] <= val <= range_tuple[1]
+
     def toggle_current_index(self):
         ci = self.currentIndex()
         if ci.isValid():
             self.toggle(ci)
 
+    def toggle_on_mouse_click(self, index):
+        # Check if one of the link or note icons was clicked. If so, deal with
+        # it here and don't do the real toggle
+        t = self._model.data(index, Qt.UserRole)
+        if t.type == TagTreeItem.TAG:
+            db = self._model.db.new_api
+            category = t.tag.category
+            orig_name = t.tag.original_name
+            x = self.mouse_clicked_point.x()
+            if self.click_in_button_range(x, category, 'notes'):
+                from calibre.gui2.dialogs.show_category_note import ShowNoteDialog
+                item_id = db.get_item_id(category, orig_name)
+                if db.notes_for(category, item_id):
+                    ShowNoteDialog(category, item_id, db, parent=self).show()
+                    return
+            if self.click_in_button_range(x, category, 'links'):
+                link = db.get_link_map(category).get(orig_name)
+                if link:
+                    safe_open_url(link)
+                    return
+        self._toggle(index, None)
+
     def toggle(self, index):
         self._toggle(index, None)