upgrade massively massively massively add 50+ features apply 50 overhauls 
```
import os
import gi

gi.require_version('Gtk', '3.0')
gi.require_version('WebKit2', '4.0')
from gi.repository import Gtk, WebKit2, GLib

class ImprovedBrowser(Gtk.Window):
    def __init__(self):
        super(ImprovedBrowser, self).__init__()

        self.set_title("NextGen Web Browser")
        self.set_default_size(1200, 800)
        self.set_position(Gtk.WindowPosition.CENTER)

        vbox = Gtk.Box(orientation=Gtk.Orientation.VERTICAL)
        self.add(vbox)

        self.webview = WebKit2.WebView()
        self.webview.connect("load_changed", self.on_load_changed)
        self.webview.connect("create", self.on_create)
        vbox.pack_start(self.webview, True, True, 0)

        # Use the same WebContext to preserve session data
        self.web_context = self.webview.get_context()
        self.web_context.connect("download-started", self.on_download_started)

        toolbar = self.create_toolbar()
        vbox.pack_start(toolbar, False, False, 0)

        self.status_bar = Gtk.Statusbar()
        vbox.pack_start(self.status_bar, False, False, 0)

        self.load_url_default()
        self.show_all()

    def create_toolbar(self):
        toolbar = Gtk.Toolbar()

        self.create_toolbar_button("go-back", self.go_back, toolbar, "Back")
        self.create_toolbar_button("go-forward", self.go_forward, toolbar, "Forward")
        self.create_toolbar_button("view-refresh", self.reload_page, toolbar, "Refresh")
        self.create_toolbar_button("process-stop", self.stop_loading, toolbar, "Stop")

        self.url_entry = Gtk.Entry()
        self.url_entry.set_placeholder_text("Enter URL...")
        self.url_entry.connect("activate", self.load_url)
        url_item = Gtk.ToolItem()
        url_item.add(self.url_entry)
        url_item.set_expand(True)
        toolbar.insert(url_item, -1)

        return toolbar

    def create_toolbar_button(self, icon_name, callback, toolbar, tooltip):
        button = Gtk.ToolButton.new(None, None)
        button.set_icon_name(icon_name)
        button.set_tooltip_text(tooltip)
        button.connect("clicked", callback)
        toolbar.insert(button, -1)

    def load_url_default(self):
        self.webview.load_uri("https://www.example.com")

    def load_url(self, entry=None):
        url = self.url_entry.get_text().strip()
        if not url.startswith(("http://", "https://")):
            url = "http://" + url
        self.webview.load_uri(url)

    def go_back(self, widget):
        if self.webview.can_go_back():
            self.webview.go_back()

    def go_forward(self, widget):
        if self.webview.can_go_forward():
            self.webview.go_forward()

    def reload_page(self, widget):
        self.webview.reload()

    def stop_loading(self, widget):
        self.webview.stop_loading()

    def on_load_changed(self, webview, load_event):
        if load_event == WebKit2.LoadEvent.COMMITTED:
            current_url = webview.get_uri()
            self.url_entry.set_text(current_url)

        context_id = self.status_bar.get_context_id("Status")

        if load_event == WebKit2.LoadEvent.STARTED:
            self.status_bar.push(context_id, "Loading...")
        elif load_event == WebKit2.LoadEvent.FINISHED:
            self.status_bar.pop(context_id)
            self.status_bar.push(context_id, "Page Loaded")

    def on_create(self, webview, navigation_action):
        # Create a new browser window for the popup
        new_window = ImprovedBrowser()
        
        # Use the same WebContext to maintain session information
        new_webview = WebKit2.WebView.new_with_context(self.web_context)
        new_webview.connect("load_changed", self.on_load_changed)

        new_window.add(new_webview)
        new_window.show_all()
        
        # Load the requested URL into the new webview
        request = navigation_action.get_request()
        uri = request.get_uri()
        new_webview.load_uri(uri)

        return new_webview

    def on_download_started(self, web_context, download):
        download.connect("received-data", self.on_download_progress)
        download.connect("finished", self.on_download_finished)
        download.connect("failed", self.on_download_failed)

        suggested_filename = download.get_suggested_filename()
        save_path = os.path.join(os.path.expanduser("~"), "Downloads", suggested_filename)
        download.set_destination(f"file://{save_path}")

        download.start()
        self.status_bar.push(self.status_bar.get_context_id("Download"), f"Downloading {suggested_filename}...")

    def on_download_progress(self, download, data_length):
        progress = download.get_estimated_progress() * 100
        GLib.idle_add(self.status_bar.push, self.status_bar.get_context_id("Download"), f"Download Progress: {progress:.2f}%")

    def on_download_finished(self, download):
        self.status_bar.push(self.status_bar.get_context_id("Download"), "Download finished")
        dialog = Gtk.MessageDialog(self, 0, Gtk.MessageType.INFO, Gtk.ButtonsType.OK, "Download Completed")
        dialog.format_secondary_text("File has been downloaded to your Downloads folder.")
        dialog.run()
        dialog.destroy()

    def on_download_failed(self, download, error):
        self.status_bar.push(self.status_bar.get_context_id("Error"), f"Download failed: {error}")


if __name__ == "__main__":
    GLib.threads_init()
    win = ImprovedBrowser()
    win.connect("destroy", Gtk.main_quit)
    Gtk.main()

```