Fix undocked Quickview dialog not being restored at startup. Fixes #2…

…060314 [Quickview panel on Calibre start](https://bugs.launchpad.net/calibre/+bug/2060314)

src/calibre/gui2/actions/show_quickview.py

@@ -8,7 +8,7 @@
 
 from qt.core import QAction, QTimer
 
-from calibre.gui2 import error_dialog
+from calibre.gui2 import error_dialog, gprefs
 from calibre.gui2.actions import InterfaceAction
 from calibre.gui2.dialogs.quickview import Quickview
 
@@ -83,6 +83,15 @@ def toggle_quick_view(self):
     def qv_button(self):
         return self.gui.layout_container.quick_view_button
 
+    def shutting_down(self):
+        is_open = True
+        if not self.current_instance or self.current_instance.is_closed:
+            is_open = False
+        gprefs.set('qv_open_at_shutdown', is_open)
+
+    def needs_show_on_startup(self):
+        return gprefs.get('qv_open_at_shutdown', False)
+
     def initialization_complete(self):
         set_quickview_action_plugin(self)
         self.qv_button.toggled.connect(self.toggle_quick_view)

src/calibre/gui2/ui.py

@@ -444,7 +444,7 @@ def initialize(self, library_path, db, actions, show_gui=True):
 
     def post_initialize_actions(self):
         # Various post-initialization actions after an event loop tick
-        if self.layout_container.is_visible.quick_view:
+        if self.layout_container.is_visible.quick_view or self.iactions['Quickview'].needs_show_on_startup():
             self.iactions['Quickview'].show_on_startup()
         self.listener.start_listening()
         self.start_smartdevice()