diff --git a/src/p_lights.cpp b/src/p_lights.cpp
index 2a52692b5..504095a40 100644
--- a/src/p_lights.cpp
+++ b/src/p_lights.cpp
@@ -191,6 +191,7 @@ DLighting::DLighting (sector_t *sector)
 	: DSectorEffect (sector)
 {
 	ChangeStatNum (STAT_LIGHT);
+	sector->lightingdata = this;
 }
 
 //-----------------------------------------------------------------------------
diff --git a/src/p_sectors.cpp b/src/p_sectors.cpp
index fb4789e17..1f65e952f 100644
--- a/src/p_sectors.cpp
+++ b/src/p_sectors.cpp
@@ -2490,9 +2490,9 @@ DEFINE_FIELD_X(Sector, sector_t, thinglist)
 DEFINE_FIELD_X(Sector, sector_t, friction)
 DEFINE_FIELD_X(Sector, sector_t, movefactor)
 DEFINE_FIELD_X(Sector, sector_t, terrainnum)
-DEFINE_FIELD_X(Sector, sector_t, floordata)
-DEFINE_FIELD_X(Sector, sector_t, ceilingdata)
-DEFINE_FIELD_X(Sector, sector_t, lightingdata)
+DEFINE_FIELD_UNSIZED(Sector, sector_t, floordata)
+DEFINE_FIELD_UNSIZED(Sector, sector_t, ceilingdata)
+DEFINE_FIELD_UNSIZED(Sector, sector_t, lightingdata)
 DEFINE_FIELD_X(Sector, sector_t, interpolations)
 DEFINE_FIELD_X(Sector, sector_t, soundtraversed)
 DEFINE_FIELD_X(Sector, sector_t, stairlock)
diff --git a/wadsrc/static/zscript/mapdata.txt b/wadsrc/static/zscript/mapdata.txt
index 99134a70a..12d4a8037 100644
--- a/wadsrc/static/zscript/mapdata.txt
+++ b/wadsrc/static/zscript/mapdata.txt
@@ -231,9 +231,9 @@ struct Sector native play
 	native int			terrainnum[2];
 
 	// thinker_t for reversable actions
-	//SectorEffect floordata;	
-	//SectorEffect ceilingdata;	
-	//SectorEffect lightingdata;
+	native SectorEffect floordata;
+	native SectorEffect ceilingdata;
+	native SectorEffect lightingdata;
 
 	enum EPlane
 	{