diff --git a/src/p_map.cpp b/src/p_map.cpp
index 2acb718c7..49277e7f0 100644
--- a/src/p_map.cpp
+++ b/src/p_map.cpp
@@ -740,7 +740,8 @@ bool PIT_CheckLine (line_t *ld, const FBoundingBox &box, FCheckPosition &tm)
 		// so don't mess around with the z-position
 		if (ld->frontsector->floorplane==ld->backsector->floorplane &&
 			ld->frontsector->floorplane==tm.thing->Sector->floorplane &&
-			!ld->frontsector->e->XFloor.ffloors.Size() && !ld->backsector->e->XFloor.ffloors.Size())
+			!ld->frontsector->e->XFloor.ffloors.Size() && !ld->backsector->e->XFloor.ffloors.Size() &&
+			!open.abovemidtex)
 		{
 			open.bottom=INT_MIN;
 		}