diff --git a/uppsrc/Turtle/Turtle.html b/uppsrc/Turtle/Turtle.html
index 681607330..3b0a1cb04 100644
--- a/uppsrc/Turtle/Turtle.html
+++ b/uppsrc/Turtle/Turtle.html
@@ -482,7 +482,7 @@ document.onkeydown = function(event)
 {
 	event_queue += "K " + event.keyCode + " " + event.which + key_flags(event);
 	ScheduleSend();
-	if(event.ctrlKey || event.altKey || event.keyCode === 8) {
+	if(event.ctrlKey || event.altKey || event.keyCode === 8 || event.keyCode == 9) {
 		event.stopPropagation();
     	event.preventDefault();
     }