fix(render): a loose list holding block references gets the index

crates/render/src/pipeline.rs

@@ -222,7 +222,8 @@ pub(crate) fn with_point_view(d: &Drawing, space: &Space, opts: &Options) -> Opt
     o
 }
 
-/// Loose entity lists shorter than this look layers up by scanning them rather than building an index.
+/// Loose entity lists shorter than this, with no block reference (whose contents expand to many
+/// objects), look layers up by scanning rather than building an index.
 const SMALL_LIST: usize = 64;
 
 /// Build the display list for a set of loose entities (previews, rubber bands).
@@ -236,7 +237,11 @@ pub fn build_entities<'a, I: IntoIterator<Item = &'a Entity>>(d: &Drawing, ents:
     } else {
         opts
     };
-    let layers = if ents.len() < SMALL_LIST { LayerIndex::linear() } else { LayerIndex::new(d) };
+    let layers = if ents.len() < SMALL_LIST && !ents.iter().any(|e| matches!(e.kind, EntityKind::Insert(_))) {
+        LayerIndex::linear()
+    } else {
+        LayerIndex::new(d)
+    };
     let mut b = Builder {
         list: DisplayList::default(),
         opts,