diff --git a/services/web/public/coffee/ide/editor/directives/aceEditor.coffee b/services/web/public/coffee/ide/editor/directives/aceEditor.coffee
index 577a3a0e75..79aad26221 100644
--- a/services/web/public/coffee/ide/editor/directives/aceEditor.coffee
+++ b/services/web/public/coffee/ide/editor/directives/aceEditor.coffee
@@ -356,6 +356,7 @@ define [
 						session.setOption("useWorker", scope.syntaxValidation);
 
 					# now attach session to editor
+					editor.setReadOnly(true) # set to readonly until document change handlers are attached
 					editor.setSession(session)
 
 					doc = session.getDocument()
@@ -364,6 +365,8 @@ define [
 					editor.initing = true
 					sharejs_doc.attachToAce(editor)
 					editor.initing = false
+					# now ready to edit document
+					editor.setReadOnly(scope.readOnly) # respect the readOnly setting, normally false
 
 					resetScrollMargins()