A new option to keep the current search when switching Virtual libraries under Preferences->Searching. Fixes #2151262 [[Enhancement] Option for persistant Search Box Text](https://bugs.launchpad.net/calibre/+bug/2151262)

Merge branch 'copilot/add-keep-search-on-library-switch' of https://github.com/kovidgoyal/calibre

src/calibre/gui2/__init__.py

@@ -496,6 +496,7 @@ def create_defs():
     defs['tb_search_order'] = {'0': 1, '1': 2, '2': 3, '3': 4, '4': 0}
     defs['search_tool_bar_shows_text'] = True
     defs['allow_keyboard_search_in_library_views'] = True
+    defs['keep_search_when_switching_vl'] = False
     defs['show_links_in_tag_browser'] = False
     defs['show_notes_in_tag_browser'] = False
     defs['icons_on_right_in_tag_browser'] = True

src/calibre/gui2/preferences/search.py

@@ -32,6 +32,7 @@ class ConfigWidget(ConfigWidgetBase, Ui_Form):
         r('use_primary_find_in_search', prefs)
         r('search_tool_bar_shows_text', gprefs)
         r('allow_keyboard_search_in_library_views', gprefs)
+        r('keep_search_when_switching_vl', gprefs)
         ossm = self.opt_saved_search_menu_is_hierarchical
         ossm.setChecked('search' in db.new_api.pref('categories_using_hierarchy', []))
         ossm.stateChanged.connect(self.changed_signal)

src/calibre/gui2/preferences/search.ui

@@ -170,6 +170,16 @@
          </property>
         </widget>
        </item>
+       <item row="8" column="0">
+        <widget class="QCheckBox" name="opt_keep_search_when_switching_vl">
+         <property name="text">
+          <string>Keep current search when switching Virtual libraries</string>
+         </property>
+         <property name="toolTip">
+          <string>&lt;p&gt;When enabled, the current search is kept and re-applied when switching Virtual libraries, instead of being cleared.&lt;/p&gt;</string>
+         </property>
+        </widget>
+       </item>
       </layout>
      </widget>
      <widget class="QWidget" name="tab_2">

src/calibre/gui2/search_restriction_mixin.py

@@ -698,7 +698,10 @@ class SearchRestrictionMixin:
         # the book count.
         self.library_view.model().db.data.set_search_restriction(restriction)
         self.library_view.model().db.data.set_search_restriction_name(name)
-        self.search.clear(emit_search=True)
+        if gprefs.get('keep_search_when_switching_vl') and self.search.current_text:
+            self.search.do_search()
+        else:
+            self.search.clear(emit_search=True)
         self.tags_view.recount()
         self.set_number_of_books_shown()
         self.focus_current_view()