Index: data.c
===================================================================
--- data.c	(revision 29717)
+++ data.c	(revision 29718)
@@ -410,7 +410,7 @@
 	PCB_END_LOOP;
 	PCB_LINE_ALL_LOOP(data);
 	{
-		pcb_line_mirror(layer, line, y_offs, undoable);
+		pcb_line_mirror(line, y_offs, undoable);
 	}
 	PCB_ENDALL_LOOP;
 	PCB_ARC_ALL_LOOP(data);