diff --git a/facade/FacadePart.java b/facade/FacadePart.java
index e0cb6b55a..db3ec849e 100644
--- a/facade/FacadePart.java
+++ b/facade/FacadePart.java
@@ -50,6 +50,7 @@ public class FacadePart implements IFacadePart
 	@Override
 	public void getBoxes(IPartCollsionHelper ch)
 	{
+		// the box is 15.9 for transition planes to pick up collision events.
 		ch.addBox( 0.0, 0.0, 14, 16.0, 16.0, 15.9 );
 	}