When a Zone moves or is removed from octree, clear zone from all drawables within the bounding box, not just from those that belong to the zone. This allows zone search in View to perform more optimally.

Source/Engine/Graphics/View.cpp

@@ -201,8 +201,8 @@ void CheckVisibilityWork(const WorkItem* item, unsigned threadIndex)
             if (drawable->GetDrawableFlags() & DRAWABLE_GEOMETRY)
             {
                 Zone* drawableZone = drawable->GetZone();
-                if (!cameraZoneOverride && (drawable->IsZoneDirty() || !drawableZone || drawableZone->GetPriority() <
-                    view->highestZonePriority_ || (drawableZone->GetViewMask() & cameraViewMask) == 0))
+                if (!cameraZoneOverride && (drawable->IsZoneDirty() || !drawableZone || (drawableZone->GetViewMask() &
+                    cameraViewMask) == 0))
                     view->FindZone(drawable);
                 
                 const BoundingBox& geomBox = drawable->GetWorldBoundingBox();

Source/Engine/Graphics/Zone.cpp

@@ -325,10 +325,7 @@ void Zone::ClearDrawablesZone()
             Drawable* drawable = *i;
             unsigned drawableFlags = drawable->GetDrawableFlags();
             if (drawableFlags & DRAWABLE_GEOMETRY)
-            {
-                if (drawable->GetZone() == this)
-                    drawable->SetZone(0);
-            }
+                drawable->SetZone(0);
             else if (drawableFlags & DRAWABLE_ZONE)
             {
                 Zone* zone = static_cast<Zone*>(drawable);