force a relayout/repaint on tab switches (white tab until F5)

F5 fixing the blank tab shows the page is loaded but WebKitGTK never
re-composites a freshly shown webview under accelerated compositing.
queue resize+draw for the active view and its container on every switch,
plus one more pass on idle, so a restored or switched-to tab lands on a
live frame instead of a stale white surface.

src/webview.rs

@@ -17,9 +17,9 @@ use tao::event_loop::{ControlFlow, EventLoop, EventLoopBuilder, EventLoopProxy};
 #[cfg(target_os = "linux")]
 use tao::platform::unix::WindowExtUnix;
 use tao::window::{Icon, Window, WindowBuilder};
-#[cfg(target_os = "linux")]
-use wry::WebViewBuilderExtUnix;
 use wry::{PageLoadEvent, Rect, WebContext, WebView, WebViewBuilder};
+#[cfg(target_os = "linux")]
+use wry::{WebViewBuilderExtUnix, WebViewExtUnix};
 
 const DEFAULT_HOME: &str = "https://duckduckgo.com";
 const NEW_TAB_URL: &str = "https://duckduckgo.com";
@@ -2311,6 +2311,34 @@ fn apply_visibility(state: &BrowserState) {
             let _ = webview.set_visible(i == state.active);
         }
     }
+    #[cfg(target_os = "linux")]
+    nudge_active_repaint(state);
+}
+
+/// WebKitGTK with accelerated compositing can leave a freshly shown webview
+/// unpainted (blank page until something forces a redraw). Re-queue layout
+/// and drawing on the active view so every tab switch lands on a live frame.
+#[cfg(target_os = "linux")]
+fn nudge_active_repaint(state: &BrowserState) {
+    let Some(tab) = state.tabs.get(state.active) else {
+        return;
+    };
+    let Some(webview) = tab.webview.as_ref() else {
+        return;
+    };
+    if let Some(container) = state.gtk_content_container.as_ref() {
+        container.queue_resize();
+    }
+    let widget = webview.webview();
+    widget.queue_resize();
+    widget.queue_draw();
+    let widget = widget.clone();
+    gtk::glib::idle_add_local_once(move || {
+        if widget.is_realized() {
+            widget.queue_resize();
+            widget.queue_draw();
+        }
+    });
 }
 
 fn push_tabs(state: &BrowserState) {