Clear history only after first page of book is loaded

src/calibre/gui2/viewer/web_view.py

@@ -254,6 +254,7 @@ class ViewerBridge(Bridge):
     show_error = from_js(object, object, object)
     export_shortcut_map = from_js(object)
     print_book = from_js()
+    clear_history = from_js()
 
     create_view = to_js()
     start_book_load = to_js()
@@ -430,6 +431,7 @@ class WebView(RestartingWebEngineView):
         self.bridge.show_loading_message.connect(self.show_loading_message)
         self.bridge.show_error.connect(self.show_error)
         self.bridge.print_book.connect(self.print_book)
+        self.bridge.clear_history.connect(self.clear_history)
         self.bridge.export_shortcut_map.connect(self.set_shortcut_map)
         self.shortcut_map = {}
         self.bridge.report_cfi.connect(self.call_callback)
@@ -504,7 +506,6 @@ class WebView(RestartingWebEngineView):
 
     def start_book_load(self, initial_cfi=None, initial_toc_node=None, initial_bookpos=None):
         key = (set_book_path.path,)
-        self.clear_history()
         self.execute_when_ready('start_book_load', key, initial_cfi, initial_toc_node, initial_bookpos, set_book_path.pathtoebook)
 
     def execute_when_ready(self, action, *args):

src/pyj/read_book/view.pyj

@@ -365,6 +365,8 @@ class View:
             self.on_next_section({'forward': True})
         elif data.name is 'previous_section':
             self.on_next_section({'forward': False})
+        elif data.name is 'open_book':
+            self.overlay.open_book()
 
     def on_selection_change(self, data):
         self.currently_showing.selected_text = data.text
@@ -571,6 +573,7 @@ class View:
         self.hide_overlays()
         self.iframe.focus()
         is_current_book = self.book and self.book.key == book.key
+        self.book_load_started = True
         if not is_current_book:
             self.iframe_wrapper.reset()
             self.content_popup_overlay.iframe_wrapper.reset()
@@ -912,6 +915,10 @@ class View:
         self.set_progress_frac(data.progress_frac, data.file_progress_frac)
         self.update_header_footer()
         window.scrollTo(0, 0)  # ensure window is at 0 on mobile where the navbar causes issues
+        if self.book_load_started:
+            self.book_load_started = False
+            if ui_operations.clear_history:
+                ui_operations.clear_history()
 
     def set_progress_frac(self, progress_frac, file_progress_frac):
         self.current_progress_frac = progress_frac or 0

src/pyj/viewer-main.pyj

@@ -346,6 +346,8 @@ if window is window.top:
         to_python.export_shortcut_map(smap)
     ui_operations.print_book = def():
         to_python.print_book()
+    ui_operations.clear_history = def():
+        to_python.clear_history()
 
     document.body.appendChild(E.div(id='view'))
     window.onerror = onerror