diff --git a/src/main/java/de/neemann/digital/gui/SaveAsHelper.java b/src/main/java/de/neemann/digital/gui/SaveAsHelper.java
index 53274df33..4abc34d5c 100644
--- a/src/main/java/de/neemann/digital/gui/SaveAsHelper.java
+++ b/src/main/java/de/neemann/digital/gui/SaveAsHelper.java
@@ -31,6 +31,9 @@ public final class SaveAsHelper {
         KNOWN.add("csv");
         KNOWN.add("gif");
         KNOWN.add("png");
+        KNOWN.add("tt2");
+        KNOWN.add("cupl");
+        KNOWN.add("jed");
     }
 
     private final Component parent;