diff --git a/lib/codemirror.js b/lib/codemirror.js
index 47c5292ff5..905976d718 100644
--- a/lib/codemirror.js
+++ b/lib/codemirror.js
@@ -1299,21 +1299,23 @@
         if (!eventInWidget(display, e)) e_preventDefault(e);
       });
 
-      on(te, "compositionstart", function() {
-        var start = cm.getCursor("from");
-        if (input.composing) input.composing.range.clear()
-        input.composing = {
-          start: start,
-          range: cm.markText(start, cm.getCursor("to"), {className: "CodeMirror-composing"})
-        };
-      });
-      on(te, "compositionend", function() {
-        if (input.composing) {
-          input.poll();
-          input.composing.range.clear();
-          input.composing = null;
-        }
-      });
+      if (!cm.options.updateWhenComposing) {
+        on(te, "compositionstart", function() {
+          var start = cm.getCursor("from");
+          if (input.composing) input.composing.range.clear()
+          input.composing = {
+            start: start,
+            range: cm.markText(start, cm.getCursor("to"), {className: "CodeMirror-composing"})
+          };
+        });
+        on(te, "compositionend", function() {
+          if (input.composing) {
+            input.poll();
+            input.composing.range.clear();
+            input.composing = null;
+          }
+        });
+      }
     },
 
     prepareSelection: function() {
@@ -1576,35 +1578,37 @@
 
       on(div, "paste", function(e) { handlePaste(e, cm); })
 
-      on(div, "compositionstart", function(e) {
-        var data = e.data;
-        input.composing = {sel: cm.doc.sel, data: data, startData: data};
-        if (!data) return;
-        var prim = cm.doc.sel.primary();
-        var line = cm.getLine(prim.head.line);
-        var found = line.indexOf(data, Math.max(0, prim.head.ch - data.length));
-        if (found > -1 && found <= prim.head.ch)
-          input.composing.sel = simpleSelection(Pos(prim.head.line, found),
-                                                Pos(prim.head.line, found + data.length));
-      });
-      on(div, "compositionupdate", function(e) {
-        input.composing.data = e.data;
-      });
-      on(div, "compositionend", function(e) {
-        var ours = input.composing;
-        if (!ours) return;
-        if (e.data != ours.startData && !/\u200b/.test(e.data))
-          ours.data = e.data;
-        // Need a small delay to prevent other code (input event,
-        // selection polling) from doing damage when fired right after
-        // compositionend.
-        setTimeout(function() {
-          if (!ours.handled)
-            input.applyComposition(ours);
-          if (input.composing == ours)
-            input.composing = null;
-        }, 50);
-      });
+      if (!cm.options.updateWhenComposing) {
+        on(div, "compositionstart", function(e) {
+          var data = e.data;
+          input.composing = {sel: cm.doc.sel, data: data, startData: data};
+          if (!data) return;
+          var prim = cm.doc.sel.primary();
+          var line = cm.getLine(prim.head.line);
+          var found = line.indexOf(data, Math.max(0, prim.head.ch - data.length));
+          if (found > -1 && found <= prim.head.ch)
+            input.composing.sel = simpleSelection(Pos(prim.head.line, found),
+                                                  Pos(prim.head.line, found + data.length));
+        });
+        on(div, "compositionupdate", function(e) {
+          input.composing.data = e.data;
+        });
+        on(div, "compositionend", function(e) {
+          var ours = input.composing;
+          if (!ours) return;
+          if (e.data != ours.startData && !/\u200b/.test(e.data))
+            ours.data = e.data;
+          // Need a small delay to prevent other code (input event,
+          // selection polling) from doing damage when fired right after
+          // compositionend.
+          setTimeout(function() {
+            if (!ours.handled)
+              input.applyComposition(ours);
+            if (input.composing == ours)
+              input.composing = null;
+          }, 50);
+        });
+      }
 
       on(div, "touchstart", function() {
         input.forceCompositionEnd();