diff --git a/src/main/scala/lisa/kernel/Printer.scala b/src/main/scala/lisa/kernel/Printer.scala
index e5e2f5b4181ad1ae9afaa04239470a16c8ed1f0e..b741d5dbb1004889884c0f347414bdc7deb8f1ab 100644
--- a/src/main/scala/lisa/kernel/Printer.scala
+++ b/src/main/scala/lisa/kernel/Printer.scala
@@ -294,6 +294,7 @@ object Printer {
                             case SCSubproof(_, _, false) => pretty("Subproof (hidden)")
                             case other => throw new Exception(s"No available method to print this proof step, consider updating Printer.scala\n$other")
                         }
+                        Seq(line)
                 }
             }
         }