diff --git a/OpenRA.Mods.Common/Traits/Mobile.cs b/OpenRA.Mods.Common/Traits/Mobile.cs
index 756b4178f1..88342de839 100644
--- a/OpenRA.Mods.Common/Traits/Mobile.cs
+++ b/OpenRA.Mods.Common/Traits/Mobile.cs
@@ -804,6 +804,7 @@ namespace OpenRA.Mods.Common.Traits
 
 		CPos? ClosestGroundCell()
 		{
+			// Creating a new CPos serves to reset a potential custom layer
 			var above = new CPos(TopLeft.X, TopLeft.Y);
 			if (CanEnterCell(above))
 				return above;