From d961dd7491a6d04aa749eee9d5faaa433ef2bd20 Mon Sep 17 00:00:00 2001
From: Will Temple <will@wtemple.net>
Date: Mon, 23 Mar 2026 10:36:33 -0400
Subject: [PATCH] Bound zxdg_decoration_manager_v1 for compositors that support
 server-side decorations. Fixed a resize deadlock. Fixed scroll box list
 rendering.

---
 lib/ui/src/layout.rs               |  8 +++++++-
 lib/ui_platform_wayland/src/lib.rs | 28 ++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/lib/ui/src/layout.rs b/lib/ui/src/layout.rs
index e9637cb..45ccba2 100644
--- a/lib/ui/src/layout.rs
+++ b/lib/ui/src/layout.rs
@@ -577,7 +577,13 @@ fn layout_element(
         text_system,
         perf_stats,
         layout_cache,
-        clip_rect,
+        // Do NOT propagate clip_rect into children: the scroll-box PushClip already clips
+        // them visually, and propagating the clip causes the layout cache to bake in
+        // culling results for a specific scroll position.  When the scroll changes, the
+        // same cache entry would replay with stale "empty" children that were culled at
+        // the previous offset.  Culling applies only at the direct-child level of the
+        // scroll box (which passes Some(viewport_rect) to layout_container_children).
+        None,
     );
 
     if pushed_clip {
diff --git a/lib/ui_platform_wayland/src/lib.rs b/lib/ui_platform_wayland/src/lib.rs
index b6ba4c0..030e0ff 100644
--- a/lib/ui_platform_wayland/src/lib.rs
+++ b/lib/ui_platform_wayland/src/lib.rs
@@ -40,6 +40,9 @@ use wayland_client::{
 use wayland_protocols::wp::cursor_shape::v1::client::{
     wp_cursor_shape_device_v1, wp_cursor_shape_manager_v1,
 };
+use wayland_protocols::xdg::decoration::zv1::client::{
+    zxdg_decoration_manager_v1, zxdg_toplevel_decoration_v1,
+};
 use wayland_protocols::wp::primary_selection::zv1::client::{
     zwp_primary_selection_device_manager_v1, zwp_primary_selection_device_v1,
     zwp_primary_selection_offer_v1, zwp_primary_selection_source_v1,
@@ -156,6 +159,8 @@ struct State {
     clipboard_device: Option<wl_data_device::WlDataDevice>,
     cursor_shape_manager: Option<wp_cursor_shape_manager_v1::WpCursorShapeManagerV1>,
     cursor_shape_device: Option<wp_cursor_shape_device_v1::WpCursorShapeDeviceV1>,
+    /// Server-side decoration handle.  Kept alive so the compositor maintains decorations.
+    _decoration: Option<zxdg_toplevel_decoration_v1::ZxdgToplevelDecorationV1>,
     primary_selection_manager:
         Option<zwp_primary_selection_device_manager_v1::ZwpPrimarySelectionDeviceManagerV1>,
     primary_selection_device: Option<zwp_primary_selection_device_v1::ZwpPrimarySelectionDeviceV1>,
@@ -318,6 +323,8 @@ impl WaylandWindow {
                 manager.get_device(&seat, &qh, ())
             },
         );
+        let decoration_manager: Option<zxdg_decoration_manager_v1::ZxdgDecorationManagerV1> =
+            globals.bind(&qh, 1..=1, ()).ok();
         let surface = compositor.create_surface(&qh, ());
         let xdg_surface = wm_base.get_xdg_surface(&surface, &qh, ());
         let toplevel = xdg_surface.get_toplevel(&qh, ());
@@ -325,6 +332,11 @@ impl WaylandWindow {
         if let Some(app_id) = spec.app_id.as_ref() {
             toplevel.set_app_id(app_id.clone());
         }
+        let decoration = decoration_manager.as_ref().map(|dm| {
+            let deco = dm.get_toplevel_decoration(&toplevel, &qh, ());
+            deco.set_mode(zxdg_toplevel_decoration_v1::Mode::ServerSide);
+            deco
+        });
 
         apply_size_constraints(&toplevel, &spec);
         if spec.maximized {
@@ -395,6 +407,7 @@ impl WaylandWindow {
                 last_selection_serial: None,
                 last_pointer_enter_serial: None,
                 cursor_icon: CursorIcon::Default,
+                _decoration: decoration,
             },
         })
     }
@@ -1355,6 +1368,19 @@ fn spawn_window_worker(
                                             );
                                             state_ref.pending_viewport = Some(current_viewport);
                                             state_ref.pending_viewport_since.get_or_insert_with(Instant::now);
+                                            // Deadlock prevention: if the app responded to the
+                                            // configure we sent (scene matches in_flight) but the
+                                            // viewport has since moved on, clear the in_flight
+                                            // marker so we can immediately send the next configure.
+                                            // Without this, viewport_request_in_flight stays set
+                                            // to the old size forever and the app is never told
+                                            // about the new viewport.
+                                            if state_ref.viewport_request_in_flight
+                                                == Some(scene.logical_size)
+                                            {
+                                                state_ref.viewport_request_in_flight = None;
+                                                maybe_request_pending_viewport(&mut state_ref);
+                                            }
                                             state_ref.window.request_redraw();
                                         } else if !state_ref.window.presentation_ready() {
                                             // Correct scene is ready but the compositor
@@ -1582,6 +1608,8 @@ delegate_noop!(
     State: ignore
         zwp_primary_selection_device_manager_v1::ZwpPrimarySelectionDeviceManagerV1
 );
+delegate_noop!(State: ignore zxdg_decoration_manager_v1::ZxdgDecorationManagerV1);
+delegate_noop!(State: ignore zxdg_toplevel_decoration_v1::ZxdgToplevelDecorationV1);
 impl Dispatch<wl_seat::WlSeat, ()> for State {
     fn event(
         state: &mut Self,