diff --git a/src/verso.rs b/src/verso.rs
index bab97d6a..f97413ca 100644
--- a/src/verso.rs
+++ b/src/verso.rs
@@ -5,7 +5,7 @@ use std::{
 };
 
 use arboard::Clipboard;
-use base::id::WebViewId;
+use base::id::{PipelineNamespace, PipelineNamespaceId, WebViewId};
 use bluetooth::BluetoothThreadFactory;
 use bluetooth_traits::BluetoothRequest;
 use canvas::canvas_paint_thread::CanvasPaintThread;
@@ -82,6 +82,8 @@ impl Verso {
         // Initialize configurations and Verso window
         let protocols = config.create_protocols();
         config.init();
+        // Reserving a namespace to create TopLevelBrowsingContextId.
+        PipelineNamespace::install(PipelineNamespaceId(0));
         let (window, rendering_context) = Window::new(evl);
         let event_loop_waker = Box::new(Waker(proxy));
         let opts = opts::get();
diff --git a/src/webview.rs b/src/webview.rs
index 6c559fa4..b44561d2 100644
--- a/src/webview.rs
+++ b/src/webview.rs
@@ -1,5 +1,5 @@
 use arboard::Clipboard;
-use base::id::{BrowsingContextId, PipelineNamespace, PipelineNamespaceId, WebViewId};
+use base::id::{BrowsingContextId, WebViewId};
 use compositing_traits::ConstellationMsg;
 use crossbeam_channel::Sender;
 use embedder_traits::{CompositorEventVariant, EmbedderMsg, PromptDefinition};
@@ -29,27 +29,6 @@ impl WebView {
         Self { webview_id, rect }
     }
 
-    /// Create a panel view from Winit window. A panel is a special web view that focus on controlling states around window.
-    /// It could be treated as the control panel or navigation bar of the window depending on usages.
-    ///
-    /// At the moment, following Web API is supported:
-    /// - Close window: `window.close()`
-    /// - Navigate to previous page: `window.prompt('PREV')`
-    /// - Navigate to next page: `window.prompt('FORWARD')`
-    /// - Refresh the page: `window.prompt('REFRESH')`
-    /// - Minimize the window: `window.prompt('MINIMIZE')`
-    /// - Maximize the window: `window.prompt('MAXIMIZE')`
-    /// - Navigate to a specific URL: `window.prompt('NAVIGATE_TO:${url}')`
-    pub fn new_panel(rect: DeviceIntRect) -> Self {
-        // Reserving a namespace to create TopLevelBrowsingContextId.
-        PipelineNamespace::install(PipelineNamespaceId(0));
-        let id = WebViewId::new();
-        Self {
-            webview_id: id,
-            rect,
-        }
-    }
-
     /// Set the webview size corresponding to the window size.
     pub fn set_size(&mut self, mut rect: DeviceIntRect) {
         rect.min.y = rect.max.y.min(100);
diff --git a/src/window.rs b/src/window.rs
index 3fa20ad4..f3bdd6cb 100644
--- a/src/window.rs
+++ b/src/window.rs
@@ -39,7 +39,17 @@ pub struct Window {
     pub(crate) window: WinitWindow,
     /// GL surface of the window
     pub(crate) surface: Surface<WindowSurface>,
-    /// The main control panel of this window.
+    /// The main panel of this window. A panel is a special web view that focus on controlling states around window.
+    /// It could be treated as the control panel or navigation bar of the window depending on usages.
+    ///
+    /// At the moment, following Web API is supported:
+    /// - Close window: `window.close()`
+    /// - Navigate to previous page: `window.prompt('PREV')`
+    /// - Navigate to next page: `window.prompt('FORWARD')`
+    /// - Refresh the page: `window.prompt('REFRESH')`
+    /// - Minimize the window: `window.prompt('MINIMIZE')`
+    /// - Maximize the window: `window.prompt('MAXIMIZE')`
+    /// - Navigate to a specific URL: `window.prompt('NAVIGATE_TO:${url}')`
     pub(crate) panel: Option<WebView>,
     /// The WebView of this window.
     pub(crate) webview: Option<WebView>,
@@ -89,7 +99,10 @@ impl Window {
             Self {
                 window,
                 surface,
-                panel: Some(WebView::new_panel(DeviceIntRect::from_size(size))),
+                panel: Some(WebView::new(
+                    WebViewId::new(),
+                    DeviceIntRect::from_size(size),
+                )),
                 webview: None,
                 mouse_position: Cell::new(PhysicalPosition::default()),
                 modifiers_state: Cell::new(ModifiersState::default()),