diff --git a/lttb.tcl b/lttb.tcl
index 1ffbbf8..47fb2c2 100755
--- a/lttb.tcl
+++ b/lttb.tcl
@@ -258,7 +258,7 @@ proc lttb_EN {stmt} {
 proc int_LIST {} {
   global progmem
   loop i 1 32768 {
-    if {[dict exists $progmem $i]} {
+    if {[dict exists $progmem $i] && [string length $progmem($i)]} {
       puts [format "%d\t%s" $i $progmem($i)]
     }
   }