diff --git a/lib/ace/autocomplete.js b/lib/ace/autocomplete.js
index 630130ba..460a62e6 100644
--- a/lib/ace/autocomplete.js
+++ b/lib/ace/autocomplete.js
@@ -40,7 +40,7 @@ var dom = require("./lib/dom");
 var snippetManager = require("./snippets").snippetManager;
 
 var Autocomplete = function() {
-    this.autoInsert = true;
+    this.autoInsert = false;
     this.autoSelect = true;
     this.exactMatch = false;
     this.gatherCompletionsId = 0;
@@ -408,10 +408,10 @@ Autocomplete.startCommand = {
     exec: function(editor) {
         if (!editor.completer)
             editor.completer = new Autocomplete();
-        editor.completer.autoInsert =
+        editor.completer.autoInsert = false;
         editor.completer.autoSelect = true;
         editor.completer.showPopup(editor);
-        // needed for firefox on mac
+        // prevent ctrl-space opening context menu on firefox on mac
         editor.completer.cancelContextMenu();
     },
     bindKey: "Ctrl-Space|Ctrl-Shift-Space|Alt-Space"
diff --git a/lib/ace/ext/language_tools.js b/lib/ace/ext/language_tools.js
index 12fcf5b2..f02390ee 100644
--- a/lib/ace/ext/language_tools.js
+++ b/lib/ace/ext/language_tools.js
@@ -140,7 +140,7 @@ var loadSnippetFile = function(id) {
 function getCompletionPrefix(editor) {
     var pos = editor.getCursorPosition();
     var line = editor.session.getLine(pos.row);
-    var prefix = util.retrievePrecedingIdentifier(line, pos.column);
+    var prefix;
     // Try to find custom prefixes on the completers
     editor.completers.forEach(function(completer) {
         if (completer.identifierRegexps) {
@@ -150,7 +150,7 @@ function getCompletionPrefix(editor) {
             });
         }
     });
-    return prefix;
+    return prefix || util.retrievePrecedingIdentifier(line, pos.column);
 }
 
 var doLiveAutocomplete = function(e) {
@@ -158,8 +158,6 @@ var doLiveAutocomplete = function(e) {
     var text = e.args || "";
     var hasCompleter = editor.completer && editor.completer.activated;
 
-
-
     // We don't want to autocomplete with no prefix
     if (e.command.name === "backspace") {
         if (hasCompleter && !getCompletionPrefix(editor))
@@ -174,7 +172,6 @@ var doLiveAutocomplete = function(e) {
                 editor.completer = new Autocomplete();
             }
             // Disable autoInsert
-            editor.completer.autoSelect = false;
             editor.completer.autoInsert = false;
             editor.completer.showPopup(editor);
         }