Fix #976727 (Right-click error)

src/calibre/gui2/dialogs/edit_authors_dialog.py

@@ -177,7 +177,7 @@ class EditAuthorsDialog(QDialog, Ui_EditAuthorsDialog):
         ca.triggered.connect(self.paste_from_clipboard)
         m.addSeparator()
 
-        if self.context_item.column() == 0:
+        if self.context_item is not None and self.context_item.column() == 0:
             ca = m.addAction(_('Copy to author sort'))
             ca.triggered.connect(self.copy_au_to_aus)
         else:

src/calibre/gui2/dialogs/user_profiles.py

@@ -108,6 +108,9 @@ class UserProfiles(ResizableDialog, Ui_Dialog):
 
     def show_recipe_files(self, *args):
         bdir = os.path.dirname(custom_recipes.file_path)
+        if not os.path.exists(bdir):
+            return error_dialog(self, _('No recipes'),
+                    _('No custom recipes created.'), show=True)
         open_local_file(bdir)
 
     def break_cycles(self):