All GUI options stuff:

1. Add the option to show the "GUI actions" button in the status bar. The code to add the Preferences button is commented out.
2. Add a shortcut to All GUI Actions: Ctrl+Alt+Shift+G
3. Fix some existing problems in the All GUI Actions implementation.
4. Add the infrastructure for status line buttons (all in init.py)
5. Make using the shortcut for All GUI Actions place the menu over the button in the status bar, if it exists and is the only button/menu item. (actions.__init__.py)

src/calibre/gui2/__init__.py

@@ -415,6 +415,8 @@ def create_defs():
     defs['tag_browser_allow_keyboard_focus'] = False
     defs['book_list_tooltips'] = True
     defs['show_layout_buttons'] = False
+    # defs['show_sb_preference_button'] = False
+    defs['show_sb_all_actions_button'] = False
     defs['bd_show_cover'] = True
     defs['bd_overlay_cover_size'] = False
     defs['tags_browser_category_icons'] = {}

src/calibre/gui2/actions/__init__.py

@@ -68,6 +68,13 @@ def show_menu_under_widget(gui, menu, action, name):
                 return
             except Exception:
                 continue
+    # Is it one of the status bar buttons?
+    for button in gui.status_bar_extra_buttons:
+        if name == button.action_name and button.isVisible():
+            r = button.geometry()
+            p = gui.status_bar
+            menu.exec(p.mapToGlobal(QPoint(r.x()+2, r.height()-2)))
+            return
     # No visible button found. Fall back to displaying in upper left corner
     # of the library view.
     menu.exec(gui.library_view.mapToGlobal(QPoint(10, 10)))

src/calibre/gui2/actions/all_actions.py

@@ -14,7 +14,7 @@ from calibre.utils.icu import sort_key
 class AllGUIActions(InterfaceAction):
 
     name = 'All GUI actions'
-    action_spec = (_('All GUI actions'), 'wizard.png',
+    action_spec = (_('GUI actions'), 'wizard.png',
                    _("Show a menu of all available GUI and plugin actions.\nThis menu "
                      "is not available when looking at books on a device"), None)
 
@@ -33,10 +33,9 @@ class AllGUIActions(InterfaceAction):
         self.shortcut_action = self.create_menu_action(
                         menu=self.hidden_menu,
                         unique_name='Main window layout',
-                        shortcut=None,
+                        shortcut='Ctrl+Shift+Alt+G',
-                        text=_("Save and restore layout item sizes, and add/remove/toggle "
+                        text=_("Show a menu of all available GUI and plugin actions."),
-                               "layout items such as the search bar, tag browser, etc. "),
+                        icon='wizard.png',
-                        icon='layout.png',
                         triggered=self.show_menu)
 
     # We want to show the menu when a shortcut is used. Apparently the only way
@@ -59,9 +58,6 @@ class AllGUIActions(InterfaceAction):
     def about_to_show_menu(self):
         self.populate_menu()
 
-    def location_selected(self, loc):
-        self.qaction.setEnabled(loc == 'library')
-
     def populate_menu(self):
         # Need to do this on every invocation because shortcuts can change
         m = self.qaction.menu()
@@ -127,13 +123,16 @@ class AllGUIActions(InterfaceAction):
             if act.popup_type == QToolButton.ToolButtonPopupMode.MenuButtonPopup:
                 if getattr(act, 'action_add_menu', None) or (getattr(act, 'qaction', None) and act.qaction.menu() and act.qaction.menu().children()):
                     # The action offers both a 'click' and a menu. Use the menu.
-                    menu.addAction(icon, menu_text, partial(self._do_menu, display_name, act))
+                    ma = menu.addAction(icon, menu_text, partial(self._do_menu, display_name, act))
                 else:
                     # The action is a dialog.
-                    menu.addAction(act.qaction.icon(), menu_text, partial(self._do_action, act))
+                    ma = menu.addAction(act.qaction.icon(), menu_text, partial(self._do_action, act))
             else:
                 # The action is a menu.
-                menu.addAction(icon, menu_text, partial(self._do_menu, display_name, act))
+                ma = menu.addAction(icon, menu_text, partial(self._do_menu, display_name, act))
+            # Disable the menu line if the underlying qaction is disabled. This
+            # happens when devices are connected and in some other contexts.
+            ma.setEnabled(act.qaction.isEnabled())
 
         # Finally the real work, building the action menu. Partition long lists
         # of actions into sublists of some arbitrary length.
@@ -166,6 +165,7 @@ class AllGUIActions(InterfaceAction):
             partition(builtin_actions)
         # Add access to the toolbars and keyboard shortcuts preferences dialogs
         m.addSection(_('Preferences') + ' ')
+        m.addAction(QIcon.ic('wizard.png'), _('Main dialog'), self.gui.iactions['Preferences'].qaction.trigger)
         m.addAction(QIcon.ic('wizard.png'), _('Toolbars'), self._do_pref_toolbar)
         m.addAction(QIcon.ic('keyboard-prefs.png'), _('Keyboard shortcuts'), self._do_pref_shortcuts)
 

src/calibre/gui2/init.py

@@ -487,6 +487,29 @@ class VLTabs(QTabBar):  # {{{
 
 # }}}
 
+class StatusBarButton(QToolButton):
+
+    def __init__(self, parent, action_name, pref_name, on_click):
+        super().__init__(parent=parent)
+        act = parent.iactions[action_name]
+        self.action_name = action_name
+        self.setCursor(Qt.CursorShape.PointingHandCursor)
+        self.setPopupMode(QToolButton.ToolButtonPopupMode.InstantPopup)
+        self.setAutoRaise(True)
+        self.setIcon(QIcon.ic(act.action_spec[1]))
+        self.setToolButtonStyle(Qt.ToolButtonStyle.ToolButtonTextBesideIcon)
+        self.setText(act.action_spec[0])
+        self.setToolTip(act.action_spec[2])
+        self.setVisible(gprefs[pref_name])
+        parent.status_bar.addPermanentWidget(self)
+        if on_click == 'menu':
+            self.setMenu(act.qaction.menu())
+        elif on_click == 'trigger':
+            self.clicked.connect(act.qaction.trigger)
+        else:
+            raise ValueError(f'make_status_line_action_button: invalid on_click ({on_click}')
+
+
 class LayoutMixin:  # {{{
 
     def __init__(self, *args, **kwargs):
@@ -573,6 +596,15 @@ class LayoutMixin:  # {{{
         b.setToolTip(_(
             'Show and hide various parts of the calibre main window'))
         self.status_bar.addPermanentWidget(b)
+
+        # These must be after the layout button because it can be expanded into
+        # the component buttons. Order: last is right-most.
+        # The preferences status bar button isn't (yet) allowed on the status bar
+        # self.sb_preferences_button = StatusBarButton(self, 'Preferences', 'show_sb_preference_button', 'trigger')
+        self.sb_all_gui_actions_button = StatusBarButton(self, 'All GUI actions',
+                                                         'show_sb_all_actions_button', 'menu')
+        self.status_bar_extra_buttons = (self.sb_all_gui_actions_button,)
+
         self.status_bar.addPermanentWidget(self.jobs_button)
         self.setStatusBar(self.status_bar)
         self.status_bar.update_label.linkActivated.connect(self.update_link_clicked)

src/calibre/gui2/preferences/look_feel.py

@@ -632,6 +632,8 @@ class ConfigWidget(ConfigWidgetBase, Ui_Form):
         r('dnd_merge', gprefs)
         r('wrap_toolbar_text', gprefs, restart_required=True)
         r('show_layout_buttons', gprefs)
+        r('show_sb_all_actions_button', gprefs)
+        # r('show_sb_preference_button', gprefs)
         r('row_numbers_in_book_list', gprefs)
         r('tag_browser_old_look', gprefs)
         r('tag_browser_hide_empty_categories', gprefs)
@@ -1277,6 +1279,8 @@ class ConfigWidget(ConfigWidgetBase, Ui_Form):
         qv = get_quickview_action_plugin()
         if qv:
             qv.refill_quickview()
+        gui.sb_all_gui_actions_button.setVisible(gprefs['show_sb_all_actions_button'])
+        # gui.sb_preferences_button.setVisible(gprefs['show_sb_preference_button'])
 
 
 if __name__ == '__main__':

src/calibre/gui2/preferences/look_feel.ui

@@ -41,6 +41,23 @@
        <item row="0" column="1">
         <widget class="QComboBox" name="opt_ui_style"/>
        </item>
+       <item row="0" column="2">
+        <layout class="QHBoxLayout">
+         <item>
+          <spacer name="horizontalSpacer_3">
+           <property name="orientation">
+            <enum>Qt::Horizontal</enum>
+           </property>
+           <property name="sizeHint" stdset="0">
+            <size>
+             <width>20</width>
+             <height>1</height>
+            </size>
+           </property>
+          </spacer>
+         </item>
+        </layout>
+       </item>
        <item row="1" column="0">
         <widget class="QLabel" name="icon_theme">
          <property name="text">
@@ -190,13 +207,6 @@
          </property>
         </widget>
        </item>
-       <item row="8" column="1">
-        <widget class="QCheckBox" name="opt_show_layout_buttons">
-         <property name="text">
-          <string>Show &amp;layout buttons in the status bar</string>
-         </property>
-        </widget>
-       </item>
        <item row="9" column="0">
         <layout class="QHBoxLayout" name="horizontalLayout">
          <item>
@@ -267,6 +277,42 @@
          </layout>
         </widget>
        </item>
+       <item row="10" column="1">
+        <widget class="QGroupBox">
+         <property name="title">
+          <string>Status bar buttons</string>
+         </property>
+         <layout class="QVBoxLayout">
+          <item>
+           <widget class="QCheckBox" name="opt_show_layout_buttons">
+            <property name="text">
+             <string>Show &amp;layout buttons</string>
+            </property>
+           </widget>
+          </item>
+          <item>
+           <widget class="QCheckBox" name="opt_show_sb_all_actions_button">
+            <property name="text">
+             <string>S&amp;how GUI actions button</string>
+            </property>
+           </widget>
+          </item>
+          <item>
+           <spacer name="horizontalSpacer_3">
+            <property name="orientation">
+             <enum>Qt::Vertical</enum>
+            </property>
+            <property name="sizeHint" stdset="0">
+             <size>
+              <width>10</width>
+              <height>20</height>
+             </size>
+            </property>
+           </spacer>
+          </item>
+         </layout>
+        </widget>
+       </item>
        <item row="11" column="0">
         <widget class="QLabel" name="label_4">
          <property name="text">