fix ie issue to convert document to screen coordinates

demo/editor.html

@@ -115,11 +115,10 @@
     </div>
     
     <script type="text/editor" id="jstext">function foo(items) {
-    for (var i=0; i<items.length; i++) {
+	for (var i=0; i<items.length; i++) {
-        alert(items[i] + "juhu";
+		alert(items[i] + "juhu";
-    }
+	}
-}
+}</script>
-    </script>
 
     <script type="text/editor" id="csstext">.text-layer {
     font-family: Monaco, "Courier New", monospace;

src/ace/VirtualRenderer.js

@@ -228,7 +228,7 @@ ace.VirtualRenderer = function(container) {
         var screenColumn = 0;
         var remaining = docColumn;
 
-        var line = this.doc.getLine(row).split(/\t/g);
+        var line = this.doc.getLine(row).split("\t");
         for (var i=0; i<line.length; i++) {
             var len = line[i].length;
             if (remaining > len) {
@@ -240,6 +240,7 @@ ace.VirtualRenderer = function(container) {
                 break;
             }
         }
+
         return screenColumn;
     };
 
@@ -249,7 +250,7 @@ ace.VirtualRenderer = function(container) {
         var docColumn = 0;
         var remaining = screenColumn;
 
-        var line = this.doc.getLine(row).split(/\t/g);
+        var line = this.doc.getLine(row).split("\t");
         for (var i=0; i<line.length; i++) {
             var len = line[i].length;
             if (remaining >= len + tabSize) {

src/test/VirtualRendererTest.js

@@ -25,6 +25,19 @@ var VirtualRendererTest = new TestCase("VirtualRendererTest", {
         assertEquals(15, renderer.$documentToScreenColumn(0, 13));
     },
 
+    "test: convert document to scrren coordinates with leading tabs": function() {
+        var el = document.createElement("div");
+        var renderer = new ace.VirtualRenderer(el);
+
+        var doc = new ace.Document("\t\t123");
+        doc.setTabSize(4);
+        renderer.setDocument(doc);
+        assertEquals(0, renderer.$documentToScreenColumn(0, 0));
+        assertEquals(4, renderer.$documentToScreenColumn(0, 1));
+        assertEquals(8, renderer.$documentToScreenColumn(0, 2));
+        assertEquals(9, renderer.$documentToScreenColumn(0, 3));
+    },
+
     "test: convert screen to document coordinates" : function() {
         var el = document.createElement("div");
         var renderer = new ace.VirtualRenderer(el);