diff --git a/src/Viewport.ts b/src/Viewport.ts
index 11889dae..8a3e4fc0 100644
--- a/src/Viewport.ts
+++ b/src/Viewport.ts
@@ -8,15 +8,19 @@ import { ITerminal } from './Interfaces';
 /**
  * Represents the viewport of a terminal, the visible area within the larger buffer of output.
  * Logic for the virtual scroll bar is included in this object.
- * @param viewportElement The DOM element acting as the viewport.
- * @param scrollArea The DOM element acting as the scroll area.
- * @param charMeasureElement A DOM element used to measure the character size of. the terminal.
  */
 export class Viewport {
   private currentRowHeight: number;
   private lastRecordedBufferLength: number;
   private lastRecordedViewportHeight: number;
 
+  /**
+   * Creates a new Viewport.
+   * @param terminal The terminal this viewport belongs to.
+   * @param viewportElement The DOM element acting as the viewport.
+   * @param scrollArea The DOM element acting as the scroll area.
+   * @param charMeasureElement A DOM element used to measure the character size of. the terminal.
+   */
   constructor(
     private terminal: ITerminal,
     private viewportElement: HTMLElement,
diff --git a/src/test/test.js b/src/test/test.js
index abdc8c17..d8e931fb 100644
--- a/src/test/test.js
+++ b/src/test/test.js
@@ -189,7 +189,7 @@ describe('xterm.js', function() {
       it('should scroll down, when a key is pressed and terminal is scrolled up', function () {
         // Override evaluateKeyEscapeSequence to return cancel code
         xterm.evaluateKeyEscapeSequence = function() {
-          return { cancel: true };
+          return { key: 'a' };
         };
         var event = {
           type: 'keydown',
@@ -200,6 +200,7 @@ describe('xterm.js', function() {
 
         xterm.ydisp = 0;
         xterm.ybase = 40;
+        assert.notEqual(xterm.ydisp, xterm.ybase);
         xterm.keyDown(event);
 
         // Ensure that now the terminal is scrolled to bottom
diff --git a/src/utils/Keyboard.test.ts b/src/utils/Keyboard.test.ts
deleted file mode 100644
index 618d3331..00000000
--- a/src/utils/Keyboard.test.ts
+++ /dev/null
@@ -1,21 +0,0 @@
-import { assert } from 'chai';
-import * as Keyboard from './Keyboard';
-
-describe('Keyboard', () => {
-  describe('isModifierOnlyKeyboardEvent', () => {
-    it('should return true when only modifier keys are used', () => {
-      // Note that KeyboardEvent.keyCode is deprecated but we're using it to improve browser
-      // compatibility. This helper returns the `any` type because KeyboardEvent doesn't exist under
-      // NodeJS.
-      function createEvent(keyCode: number): any {
-        return { keyCode };
-      }
-      assert.isTrue(Keyboard.isModifierOnlyKeyboardEvent(createEvent(16)));
-      assert.isTrue(Keyboard.isModifierOnlyKeyboardEvent(createEvent(17)));
-      assert.isTrue(Keyboard.isModifierOnlyKeyboardEvent(createEvent(18)));
-      assert.isTrue(Keyboard.isModifierOnlyKeyboardEvent(createEvent(91)));
-      assert.isFalse(Keyboard.isModifierOnlyKeyboardEvent(createEvent(19)));
-      assert.isFalse(Keyboard.isModifierOnlyKeyboardEvent(createEvent(90)));
-    });
-  });
-});
diff --git a/src/utils/Keyboard.ts b/src/utils/Keyboard.ts
deleted file mode 100644
index e43cba45..00000000
--- a/src/utils/Keyboard.ts
+++ /dev/null
@@ -1,22 +0,0 @@
-/**
- * xterm.js: xterm, in the browser
- * Copyright (c) 2016, SourceLair Private Company <www.sourcelair.com> (MIT License)
- */
-
-/**
- * Keyboard utilities module. This module contains utilities for dealing with keyboard interaction.
- * @module xterm/utils/Keyboard
- */
-
-/**
- * Gets whether a KeyboardEvent is made up entirely of modifier keys.
- *
- * @param event The event to check.
- * @return Whether the KeyboardEvent is made up entirely of modifier keys.
- */
-export function isModifierOnlyKeyboardEvent(event: KeyboardEvent): boolean {
-  return event.keyCode === 16 || // Shift
-      event.keyCode === 17 || // Control
-      event.keyCode === 18 || // Alt
-      event.keyCode === 91; // Meta
-}
diff --git a/src/xterm.js b/src/xterm.js
index 0ef9427d..752d832c 100644
--- a/src/xterm.js
+++ b/src/xterm.js
@@ -2430,12 +2430,10 @@ Terminal.prototype.keyDown = function(ev) {
     return false;
   }
 
-  // Scroll down to prompt, whenever the user presses a key.
-  if (!Keyboard.isModifierOnlyKeyboardEvent(ev) && this.ybase !== this.ydisp) {
-    this.scrollToBottom();
-  }
-
   if (!this.compositionHelper.keydown.bind(this.compositionHelper)(ev)) {
+    if (this.ybase !== this.ydisp) {
+      this.scrollToBottom();
+    }
     return false;
   }
 
@@ -2460,6 +2458,11 @@ Terminal.prototype.keyDown = function(ev) {
     return true;
   }
 
+  // Scroll down to prompt, whenever the user presses a key.
+  if (this.ybase !== this.ydisp) {
+    this.scrollToBottom();
+  }
+
   this.emit('keydown', ev);
   this.emit('key', result.key, ev);
   this.showCursor();
@@ -2724,10 +2727,13 @@ Terminal.prototype.evaluateKeyEscapeSequence = function(ev) {
           // delete
           result.key = String.fromCharCode(127);
         } else if (ev.keyCode === 219) {
-          // ^[ - escape
+          // ^[ - Control Sequence Introducer (CSI)
           result.key = String.fromCharCode(27);
+        } else if (ev.keyCode === 220) {
+          // ^\ - String Terminator (ST)
+          result.key = String.fromCharCode(28);
         } else if (ev.keyCode === 221) {
-          // ^] - group sep
+          // ^] - Operating System Command (OSC)
           result.key = String.fromCharCode(29);
         }
       } else if (!this.browser.isMac && ev.altKey && !ev.ctrlKey && !ev.metaKey) {
@@ -5129,7 +5135,6 @@ var wcwidth = (function(opts) {
  */
 
 Terminal.EventEmitter = EventEmitter;
-Terminal.Viewport = Viewport;
 Terminal.inherits = inherits;
 
 /**