diff --git a/src/calibre/gui2/viewer/ui.py b/src/calibre/gui2/viewer/ui.py
index 91cae9e0de..d4a7e53796 100644
--- a/src/calibre/gui2/viewer/ui.py
+++ b/src/calibre/gui2/viewer/ui.py
@@ -333,8 +333,8 @@ class EbookViewer(MainWindow):
         else:
             self.highlights_widget.focus()
 
-    def toggle_lookup(self):
-        self.lookup_dock.setVisible(not self.lookup_dock.isVisible())
+    def toggle_lookup(self, force_show=False):
+        self.lookup_dock.setVisible(force_show or not self.lookup_dock.isVisible())
 
     def toc_clicked(self, index):
         item = self.toc_model.itemFromIndex(index)
diff --git a/src/calibre/gui2/viewer/web_view.py b/src/calibre/gui2/viewer/web_view.py
index 42ee8f55d2..0dcb91c6f1 100644
--- a/src/calibre/gui2/viewer/web_view.py
+++ b/src/calibre/gui2/viewer/web_view.py
@@ -240,7 +240,7 @@ class ViewerBridge(Bridge):
     toggle_highlights = from_js()
     new_bookmark = from_js()
     toggle_inspector = from_js()
-    toggle_lookup = from_js()
+    toggle_lookup = from_js(object)
     show_search = from_js()
     search_result_not_found = from_js(object)
     find_next = from_js(object)
@@ -437,7 +437,7 @@ class WebView(RestartingWebEngineView):
     toggle_highlights = pyqtSignal()
     new_bookmark = pyqtSignal()
     toggle_inspector = pyqtSignal()
-    toggle_lookup = pyqtSignal()
+    toggle_lookup = pyqtSignal(object)
     quit = pyqtSignal()
     update_current_toc_nodes = pyqtSignal(object, object)
     toggle_full_screen = pyqtSignal()
diff --git a/src/pyj/read_book/overlay.pyj b/src/pyj/read_book/overlay.pyj
index 0931c0cdd6..f97a8ed5b0 100644
--- a/src/pyj/read_book/overlay.pyj
+++ b/src/pyj/read_book/overlay.pyj
@@ -320,7 +320,7 @@ class MainOverlay:  # {{{
         if runtime.is_standalone_viewer:
             actions_div.appendChild(E.ul(
                 ac(_('Lookup/search word'), _('Lookup or search for the currently selected word'),
-                   def(): self.overlay.hide(), ui_operations.toggle_lookup();, 'library')
+                   def(): self.overlay.hide(), ui_operations.toggle_lookup(True);, 'library')
             ))
             actions_div.lastChild.appendChild(highlight_action)
             actions_div.lastChild.appendChild(