diff --git a/src/textual/_compositor.py b/src/textual/_compositor.py
index fb1a642d5..115dafa9f 100644
--- a/src/textual/_compositor.py
+++ b/src/textual/_compositor.py
@@ -603,11 +603,11 @@ class Compositor:
                         if fixed:
                             widget_region = sub_region + placement_offset
                         else:
-                            # total_region = total_region.union(
-                            #     sub_region.grow(
-                            #         margin if layer_index else margin + scroll_spacing
-                            #     )
-                            # )
+                            total_region = total_region.union(
+                                sub_region.grow(
+                                    margin if layer_index else margin + scroll_spacing
+                                )
+                            )
                             widget_region = sub_region + placement_scroll_offset
 
                         widget_order = order + ((layer_index, z, layer_order),)