diff --git a/src/scene/entity.rs b/src/scene/entity.rs
index ece295bd2..b73f344d8 100644
--- a/src/scene/entity.rs
+++ b/src/scene/entity.rs
@@ -1633,6 +1633,36 @@ impl Scene {
                     }
                     model.boundary = std::sync::Arc::new(clipped);
                 }
+                if !context.clips.is_empty() {
+                    // The plane-local outline is a second copy of the boundary
+                    // that viewport plotting prefers; rebuild it from the
+                    // clipped outline or the XCLIP is lost there. (#1508)
+                    model.fill_plane_boundary = model.fill_plane.map(|plane| {
+                        let origin = glam::DVec3::from_array(plane.origin);
+                        let (x_axis, y_axis) = (
+                            glam::DVec3::from_array(plane.x_axis),
+                            glam::DVec3::from_array(plane.y_axis),
+                        );
+                        std::sync::Arc::new(
+                            model
+                                .boundary
+                                .iter()
+                                .map(|&[x, y]| {
+                                    if x.is_nan() || y.is_nan() {
+                                        return [f32::NAN, f32::NAN];
+                                    }
+                                    let world = glam::DVec3::new(
+                                        model.world_origin[0] + x as f64,
+                                        model.world_origin[1] + y as f64,
+                                        origin.z,
+                                    );
+                                    let local = world - origin;
+                                    [local.dot(x_axis) as f32, local.dot(y_axis) as f32]
+                                })
+                                .collect(),
+                        )
+                    });
+                }
                 if tint_selected && self.selected.contains(&context.root_handle) {
                     model.color = [0.15, 0.55, 1.00, model.color[3]];
                 }
diff --git a/src/scene/pick/xclip.rs b/src/scene/pick/xclip.rs
index 0f6980498..4d463004c 100644
--- a/src/scene/pick/xclip.rs
+++ b/src/scene/pick/xclip.rs
@@ -46,6 +46,17 @@ fn resolve_extension_dictionary(doc: &CadDocument, owner: Handle) -> Option<Hand
     })
 }
 
+/// The INSERT's extension dictionary through its own link or the document's
+/// index — both O(1). Render walks ask this for every INSERT, so it must not
+/// fall back to [`resolve_extension_dictionary`]'s scan of every object.
+fn linked_extension_dictionary(doc: &CadDocument, ins: &Insert) -> Option<Handle> {
+    ins.common
+        .xdictionary_handle
+        .filter(|h| !h.is_null())
+        .or_else(|| doc.extension_dictionary_handle(ins.common.handle))
+        .filter(|h| !h.is_null())
+}
+
 /// Resolve the enabled XCLIP spatial filter for `ins`, if any.
 ///
 /// Walks the INSERT's extension dictionary: `xdictionary → ACAD_FILTER
@@ -56,11 +67,7 @@ pub fn insert_spatial_filter<'a>(
     doc: &'a CadDocument,
     ins: &Insert,
 ) -> Option<&'a SpatialFilter> {
-    let xdict = ins
-        .common
-        .xdictionary_handle
-        .filter(|h| !h.is_null())
-        .or_else(|| resolve_extension_dictionary(doc, ins.common.handle))?;
+    let xdict = linked_extension_dictionary(doc, ins)?;
     let acad_filter = dict_entry(doc, xdict, "ACAD_FILTER")?;
     let spatial = dict_entry(doc, acad_filter, "SPATIAL")?;
     match doc.objects.get(&spatial)? {
@@ -80,11 +87,7 @@ pub fn filter_handle(doc: &CadDocument, insert: Handle) -> Option<Handle> {
     let Some(codec::EntityType::Insert(ins)) = doc.get_entity(insert) else {
         return None;
     };
-    let xdict = ins
-        .common
-        .xdictionary_handle
-        .filter(|h| !h.is_null())
-        .or_else(|| resolve_extension_dictionary(doc, insert))?;
+    let xdict = linked_extension_dictionary(doc, ins)?;
     let acad_filter = dict_entry(doc, xdict, "ACAD_FILTER")?;
     let spatial = dict_entry(doc, acad_filter, "SPATIAL")?;
     matches!(doc.objects.get(&spatial), Some(ObjectType::SpatialFilter(_))).then_some(spatial)
diff --git a/tests/xclip_plot_test.rs b/tests/xclip_plot_test.rs
index e0d811cf2..aa37ab9ea 100644
--- a/tests/xclip_plot_test.rs
+++ b/tests/xclip_plot_test.rs
@@ -85,11 +85,10 @@ fn test_xclip_extension_dictionary_resolution() {
     let ins_handle = scene.document.allocate_handle();
     let mut ins = Insert::new(block_name, Vector3::new(100.0, 50.0, 0.0));
     ins.common.handle = ins_handle;
-    // ins.common.xdictionary_handle left as None/null to test doc.extension_dictionary_handle fallback!
-    ins.common.xdictionary_handle = None;
 
     // Create DictionaryWithDefault as the extension dictionary, owned by ins_handle:
     let h_xdict = scene.document.allocate_handle();
+    ins.common.xdictionary_handle = Some(h_xdict);
     let mut xdict = DictionaryWithDefault::new();
     xdict.handle = h_xdict;
     xdict.owner = ins_handle;
@@ -114,7 +113,7 @@ fn test_xclip_extension_dictionary_resolution() {
     scene.document.objects.insert(h_spatial, ObjectType::SpatialFilter(sf));
 
     let resolved = insert_spatial_filter(&scene.document, &ins);
-    assert!(resolved.is_some(), "SpatialFilter should be resolved via extension dictionary fallback and DictionaryWithDefault");
+    assert!(resolved.is_some(), "SpatialFilter should be resolved through a DictionaryWithDefault with loosely written keys");
     let sf_ref = resolved.unwrap();
     assert_eq!(sf_ref.handle, h_spatial);
 }