diff --git a/lib/codemirror.js b/lib/codemirror.js
index 728b7faef45..ad29f175a83 100644
--- a/lib/codemirror.js
+++ b/lib/codemirror.js
@@ -1294,7 +1294,7 @@ window.CodeMirror = (function() {
       if (bidi ? to == from || to == moveVisually(lineObj, from, 1) : to - from <= 1) {
         var ch = x < fromX || x - fromX <= toX - x ? from : to;
         var xDiff = x - (ch == from ? fromX : toX);
-        while (isExtendingChar.test(lineObj.text.charAt(ch))) ++ch;
+        while (isExtendingChar(lineObj.text.charAt(ch))) ++ch;
         var pos = PosWithInfo(lineNo, ch, ch == from ? fromOutside : toOutside,
                               xDiff < 0 ? -1 : xDiff ? 1 : 0);
         return pos;
@@ -4581,13 +4581,12 @@ window.CodeMirror = (function() {
   function buildTokenMeasure(builder, text, style, startStyle, endStyle) {
     var wrapping = builder.cm.options.lineWrapping;
     for (var i = 0; i < text.length; ++i) {
-      var ch = text.charAt(i), start = i == 0;
-      if (ch >= "\ud800" && ch < "\udbff" && i < text.length - 1) {
-        ch = text.slice(i, i + 2);
-        ++i;
-      } else if (i && wrapping && spanAffectsWrapping(text, i)) {
+      var start = i == 0, to = i + 1;
+      while (to < text.length && isExtendingChar(text.charAt(to))) ++to;
+      var ch = text.slice(i, to);
+      i = to - 1;
+      if (i && wrapping && spanAffectsWrapping(text, i))
         builder.pre.appendChild(elt("wbr"));
-      }
       var old = builder.measure[builder.pos];
       var span = builder.measure[builder.pos] =
         buildToken(builder, ch, style,
@@ -5604,7 +5603,8 @@ window.CodeMirror = (function() {
     return true;
   }
 
-  var isExtendingChar = /[\u0300-\u036F\u0483-\u0487\u0488-\u0489\u0591-\u05BD\u05BF\u05C1-\u05C2\u05C4-\u05C5\u05C7\u0610-\u061A\u064B-\u065F\u0670\u06D6-\u06DC\u06DF-\u06E4\u06E7-\u06E8\u06EA-\u06ED\uA66F\u1DC0-\u1DFF\u20D0-\u20FF\uA670-\uA672\uA674-\uA67D\uA69F\udc00-\udfff\uFE20-\uFE2F]/;
+  var extendingChars = /[\u0300-\u036f\u0483-\u0489\u0591-\u05bd\u05bf\u05c1\u05c2\u05c4\u05c5\u05c7\u0610-\u061a\u064b-\u065e\u0670\u06d6-\u06dc\u06de-\u06e4\u06e7\u06e8\u06ea-\u06ed\u0711\u0730-\u074a\u07a6-\u07b0\u07eb-\u07f3\u0816-\u0819\u081b-\u0823\u0825-\u0827\u0829-\u082d\u0900-\u0902\u093c\u0941-\u0948\u094d\u0951-\u0955\u0962\u0963\u0981\u09bc\u09be\u09c1-\u09c4\u09cd\u09d7\u09e2\u09e3\u0a01\u0a02\u0a3c\u0a41\u0a42\u0a47\u0a48\u0a4b-\u0a4d\u0a51\u0a70\u0a71\u0a75\u0a81\u0a82\u0abc\u0ac1-\u0ac5\u0ac7\u0ac8\u0acd\u0ae2\u0ae3\u0b01\u0b3c\u0b3e\u0b3f\u0b41-\u0b44\u0b4d\u0b56\u0b57\u0b62\u0b63\u0b82\u0bbe\u0bc0\u0bcd\u0bd7\u0c3e-\u0c40\u0c46-\u0c48\u0c4a-\u0c4d\u0c55\u0c56\u0c62\u0c63\u0cbc\u0cbf\u0cc2\u0cc6\u0ccc\u0ccd\u0cd5\u0cd6\u0ce2\u0ce3\u0d3e\u0d41-\u0d44\u0d4d\u0d57\u0d62\u0d63\u0dca\u0dcf\u0dd2-\u0dd4\u0dd6\u0ddf\u0e31\u0e34-\u0e3a\u0e47-\u0e4e\u0eb1\u0eb4-\u0eb9\u0ebb\u0ebc\u0ec8-\u0ecd\u0f18\u0f19\u0f35\u0f37\u0f39\u0f71-\u0f7e\u0f80-\u0f84\u0f86\u0f87\u0f90-\u0f97\u0f99-\u0fbc\u0fc6\u102d-\u1030\u1032-\u1037\u1039\u103a\u103d\u103e\u1058\u1059\u105e-\u1060\u1071-\u1074\u1082\u1085\u1086\u108d\u109d\u135f\u1712-\u1714\u1732-\u1734\u1752\u1753\u1772\u1773\u17b7-\u17bd\u17c6\u17c9-\u17d3\u17dd\u180b-\u180d\u18a9\u1920-\u1922\u1927\u1928\u1932\u1939-\u193b\u1a17\u1a18\u1a56\u1a58-\u1a5e\u1a60\u1a62\u1a65-\u1a6c\u1a73-\u1a7c\u1a7f\u1b00-\u1b03\u1b34\u1b36-\u1b3a\u1b3c\u1b42\u1b6b-\u1b73\u1b80\u1b81\u1ba2-\u1ba5\u1ba8\u1ba9\u1c2c-\u1c33\u1c36\u1c37\u1cd0-\u1cd2\u1cd4-\u1ce0\u1ce2-\u1ce8\u1ced\u1dc0-\u1de6\u1dfd-\u1dff\u200c\u200d\u20d0-\u20f0\u2cef-\u2cf1\u2de0-\u2dff\u302a-\u302f\u3099\u309a\ua66f-\ua672\ua67c\ua67d\ua6f0\ua6f1\ua802\ua806\ua80b\ua825\ua826\ua8c4\ua8e0-\ua8f1\ua926-\ua92d\ua947-\ua951\ua980-\ua982\ua9b3\ua9b6-\ua9b9\ua9bc\uaa29-\uaa2e\uaa31\uaa32\uaa35\uaa36\uaa43\uaa4c\uaab0\uaab2-\uaab4\uaab7\uaab8\uaabe\uaabf\uaac1\uabe5\uabe8\uabed\ufb1e\ufe00-\ufe0f\ufe20-\ufe26\uff9e\uff9f]/;
+  function isExtendingChar(ch) { return ch.charCodeAt(0) >= 768 && extendingChars.test(ch); }
 
   // DOM UTILITIES
 
@@ -5831,7 +5831,7 @@ window.CodeMirror = (function() {
   function moveInLine(line, pos, dir, byUnit) {
     if (!byUnit) return pos + dir;
     do pos += dir;
-    while (pos > 0 && isExtendingChar.test(line.text.charAt(pos)));
+    while (pos > 0 && isExtendingChar(line.text.charAt(pos)));
     return pos;
   }
 
@@ -5866,7 +5866,7 @@ window.CodeMirror = (function() {
 
   function moveLogically(line, start, dir, byUnit) {
     var target = start + dir;
-    if (byUnit) while (target > 0 && isExtendingChar.test(line.text.charAt(target))) target += dir;
+    if (byUnit) while (target > 0 && isExtendingChar(line.text.charAt(target))) target += dir;
     return target < 0 || target > line.text.length ? null : target;
   }