diff --git a/demo/client.ts b/demo/client.ts
index d5196d37..6c69899e 100644
--- a/demo/client.ts
+++ b/demo/client.ts
@@ -235,7 +235,7 @@ function initOptions(term: TerminalType): void {
   });
   html += '</div><div class="option-group">';
   numberOptions.forEach(o => {
-    html += `<div class="option"><label>${o} <input id="opt-${o}" type="number" value="${term.getOption(o)}"/></label></div>`;
+    html += `<div class="option"><label>${o} <input id="opt-${o}" type="number" value="${term.getOption(o)}" step="${o === 'lineHeight' ? '0.1' : '1'}"/></label></div>`;
   });
   html += '</div><div class="option-group">';
   Object.keys(stringOptions).forEach(o => {
@@ -265,7 +265,7 @@ function initOptions(term: TerminalType): void {
       if (o === 'cols' || o === 'rows') {
         updateTerminalSize();
       } else {
-        term.setOption(o, parseInt(input.value, 10));
+        term.setOption(o, o === 'lineHeight' ? parseFloat(input.value) : parseInt(input.value, 10));
       }
     });
   });
diff --git a/src/Buffer.test.ts b/src/Buffer.test.ts
index db8a460d..2561ce36 100644
--- a/src/Buffer.test.ts
+++ b/src/Buffer.test.ts
@@ -7,7 +7,7 @@ import { assert, expect } from 'chai';
 import { ITerminal } from './Types';
 import { Buffer, DEFAULT_ATTR, CHAR_DATA_CHAR_INDEX } from './Buffer';
 import { CircularList } from './common/CircularList';
-import { MockTerminal, TestTerminal } from './utils/TestUtils.test';
+import { MockTerminal, TestTerminal } from './ui/TestUtils.test';
 import { BufferLine } from './BufferLine';
 
 const INIT_COLS = 80;
diff --git a/src/BufferSet.test.ts b/src/BufferSet.test.ts
index 38f2ddab..26f9cd42 100644
--- a/src/BufferSet.test.ts
+++ b/src/BufferSet.test.ts
@@ -7,7 +7,7 @@ import { assert } from 'chai';
 import { ITerminal } from './Types';
 import { BufferSet } from './BufferSet';
 import { Buffer } from './Buffer';
-import { MockTerminal } from './utils/TestUtils.test';
+import { MockTerminal } from './ui/TestUtils.test';
 
 describe('BufferSet', () => {
   let terminal: ITerminal;
diff --git a/src/CharWidth.test.ts b/src/CharWidth.test.ts
index d4ddd24c..0747fdf1 100644
--- a/src/CharWidth.test.ts
+++ b/src/CharWidth.test.ts
@@ -3,7 +3,7 @@
  * @license MIT
  */
 
-import { TestTerminal } from './utils/TestUtils.test';
+import { TestTerminal } from './ui/TestUtils.test';
 import { assert } from 'chai';
 import { getStringCellWidth, wcwidth } from './CharWidth';
 import { IBuffer } from './Types';
diff --git a/src/InputHandler.test.ts b/src/InputHandler.test.ts
index b2fea06a..acc18ea5 100644
--- a/src/InputHandler.test.ts
+++ b/src/InputHandler.test.ts
@@ -5,7 +5,7 @@
 
 import { assert, expect } from 'chai';
 import { InputHandler } from './InputHandler';
-import { MockInputHandlingTerminal } from './utils/TestUtils.test';
+import { MockInputHandlingTerminal } from './ui/TestUtils.test';
 import { NULL_CELL_CHAR, NULL_CELL_CODE, NULL_CELL_WIDTH, CHAR_DATA_CHAR_INDEX, CHAR_DATA_ATTR_INDEX, DEFAULT_ATTR } from './Buffer';
 import { Terminal } from './Terminal';
 import { IBufferLine } from './Types';
diff --git a/src/Linkifier.test.ts b/src/Linkifier.test.ts
index 22e797aa..0ba1294a 100644
--- a/src/Linkifier.test.ts
+++ b/src/Linkifier.test.ts
@@ -7,7 +7,7 @@ import { assert } from 'chai';
 import { IMouseZoneManager, IMouseZone } from './ui/Types';
 import { ILinkMatcher, ITerminal, IBufferLine } from './Types';
 import { Linkifier } from './Linkifier';
-import { MockBuffer, MockTerminal, TestTerminal } from './utils/TestUtils.test';
+import { MockBuffer, MockTerminal, TestTerminal } from './ui/TestUtils.test';
 import { CircularList } from './common/CircularList';
 import { BufferLine } from './BufferLine';
 
diff --git a/src/SelectionManager.test.ts b/src/SelectionManager.test.ts
index 8735e894..2f74ccda 100644
--- a/src/SelectionManager.test.ts
+++ b/src/SelectionManager.test.ts
@@ -9,7 +9,7 @@ import { SelectionManager, SelectionMode } from './SelectionManager';
 import { SelectionModel } from './SelectionModel';
 import { BufferSet } from './BufferSet';
 import { ITerminal, IBuffer, IBufferLine } from './Types';
-import { MockTerminal } from './utils/TestUtils.test';
+import { MockTerminal } from './ui/TestUtils.test';
 import { BufferLine } from './BufferLine';
 
 class TestMockTerminal extends MockTerminal {
diff --git a/src/SelectionManager.ts b/src/SelectionManager.ts
index 3dc50271..4bac0400 100644
--- a/src/SelectionManager.ts
+++ b/src/SelectionManager.ts
@@ -5,7 +5,7 @@
 
 import { ITerminal, ISelectionManager, IBuffer, CharData, IBufferLine } from './Types';
 import { XtermListener } from './common/Types';
-import { MouseHelper } from './utils/MouseHelper';
+import { MouseHelper } from './ui/MouseHelper';
 import * as Browser from './core/Platform';
 import { CharMeasure } from './ui/CharMeasure';
 import { EventEmitter } from './common/EventEmitter';
diff --git a/src/SelectionModel.test.ts b/src/SelectionModel.test.ts
index 59b2ce75..8d4b30bb 100644
--- a/src/SelectionModel.test.ts
+++ b/src/SelectionModel.test.ts
@@ -7,7 +7,7 @@ import { assert } from 'chai';
 import { ITerminal } from './Types';
 import { SelectionModel } from './SelectionModel';
 import { BufferSet } from './BufferSet';
-import { MockTerminal } from './utils/TestUtils.test';
+import { MockTerminal } from './ui/TestUtils.test';
 
 class TestSelectionModel extends SelectionModel {
   constructor(
diff --git a/src/Terminal.test.ts b/src/Terminal.test.ts
index fd59144c..733d2b39 100644
--- a/src/Terminal.test.ts
+++ b/src/Terminal.test.ts
@@ -5,7 +5,7 @@
 
 import { assert, expect } from 'chai';
 import { Terminal } from './Terminal';
-import { MockViewport, MockCompositionHelper, MockRenderer } from './utils/TestUtils.test';
+import { MockViewport, MockCompositionHelper, MockRenderer } from './ui/TestUtils.test';
 import { CHAR_DATA_CHAR_INDEX, CHAR_DATA_WIDTH_INDEX, DEFAULT_ATTR } from './Buffer';
 
 const INIT_COLS = 80;
diff --git a/src/Terminal.ts b/src/Terminal.ts
index 2cfc1ca8..bc8fb103 100644
--- a/src/Terminal.ts
+++ b/src/Terminal.ts
@@ -39,8 +39,7 @@ import { CharMeasure } from './ui/CharMeasure';
 import * as Browser from './core/Platform';
 import { addDisposableDomListener } from './ui/Lifecycle';
 import * as Strings from './Strings';
-import { MouseHelper } from './utils/MouseHelper';
-import { clone } from './utils/Clone';
+import { MouseHelper } from './ui/MouseHelper';
 import { DEFAULT_BELL_SOUND, SoundManager } from './SoundManager';
 import { DEFAULT_ANSI_COLORS } from './renderer/ColorManager';
 import { MouseZoneManager } from './ui/MouseZoneManager';
@@ -52,6 +51,7 @@ import { DomRenderer } from './renderer/dom/DomRenderer';
 import { IKeyboardEvent } from './common/Types';
 import { evaluateKeyboardEvent } from './core/input/Keyboard';
 import { KeyboardResultType, ICharset } from './core/Types';
+import { clone } from './common/Clone';
 
 // Let it work inside Node.js for automated testing purposes.
 const document = (typeof window !== 'undefined') ? window.document : null;
@@ -464,6 +464,7 @@ export class Terminal extends EventEmitter implements ITerminal, IDisposable, II
           this.renderer.onResize(this.cols, this.rows);
           this.refresh(0, this.rows - 1);
         }
+        break;
       case 'rendererType':
         if (this.renderer) {
           this.unregister(this.renderer);
diff --git a/src/Types.ts b/src/Types.ts
index 430c6575..a5aa8add 100644
--- a/src/Types.ts
+++ b/src/Types.ts
@@ -245,7 +245,7 @@ export interface ILinkifierAccessor {
 }
 
 export interface IMouseHelper {
-  getCoords(event: { pageX: number, pageY: number }, element: HTMLElement, charMeasure: ICharMeasure, colCount: number, rowCount: number, isSelection?: boolean): [number, number];
+  getCoords(event: { clientX: number, clientY: number }, element: HTMLElement, charMeasure: ICharMeasure, colCount: number, rowCount: number, isSelection?: boolean): [number, number];
   getRawByteCoords(event: MouseEvent, element: HTMLElement, charMeasure: ICharMeasure, colCount: number, rowCount: number): { x: number, y: number };
 }
 
diff --git a/src/utils/Clone.test.ts b/src/common/Clone.test.ts
similarity index 95%
rename from src/utils/Clone.test.ts
rename to src/common/Clone.test.ts
index b24452c8..4b815ff3 100644
--- a/src/utils/Clone.test.ts
+++ b/src/common/Clone.test.ts
@@ -101,7 +101,7 @@ describe('clone', () => {
     test.a.b.c.d.e.f = 'bar';
 
     // The values at a greater depth then 5 should not be cloned
-    assert.equal(cloned.a.b.c.d.e.f, 'bar');
+    assert.equal((cloned as any).a.b.c.d.e.f, 'bar');
   });
 
   it('should allow an optional maximum depth to be set', () => {
@@ -118,7 +118,7 @@ describe('clone', () => {
     test.a.b.c = 'bar';
 
     // The values at a greater depth then 2 should not be cloned
-    assert.equal(cloned.a.b.c, 'bar');
+    assert.equal((cloned as any).a.b.c, 'bar');
   });
 
   it('should not throw when cloning a recursive reference', () => {
diff --git a/src/utils/Clone.ts b/src/common/Clone.ts
similarity index 90%
rename from src/utils/Clone.ts
rename to src/common/Clone.ts
index b09c0258..78bacbb5 100644
--- a/src/utils/Clone.ts
+++ b/src/common/Clone.ts
@@ -6,7 +6,7 @@
 /*
  * A simple utility for cloning values
  */
-export const clone = <T>(val: T, depth: number = 5): T => {
+export function clone<T>(val: T, depth: number = 5): T | null {
   if (typeof val !== 'object') {
     return val;
   }
@@ -25,4 +25,4 @@ export const clone = <T>(val: T, depth: number = 5): T => {
   }
 
   return clonedObject as T;
-};
+}
diff --git a/src/renderer/CharacterJoinerRegistry.test.ts b/src/renderer/CharacterJoinerRegistry.test.ts
index 383d2a7f..0c29566a 100644
--- a/src/renderer/CharacterJoinerRegistry.test.ts
+++ b/src/renderer/CharacterJoinerRegistry.test.ts
@@ -1,6 +1,6 @@
 import { assert } from 'chai';
 
-import { MockTerminal, MockBuffer } from '../utils/TestUtils.test';
+import { MockTerminal, MockBuffer } from '../ui/TestUtils.test';
 import { CircularList } from '../common/CircularList';
 
 import { ICharacterJoinerRegistry } from './Types';
diff --git a/src/renderer/atlas/CharAtlasCache.ts b/src/renderer/atlas/CharAtlasCache.ts
index 3cb0e1cd..388a181b 100644
--- a/src/renderer/atlas/CharAtlasCache.ts
+++ b/src/renderer/atlas/CharAtlasCache.ts
@@ -42,8 +42,6 @@ export function acquireCharAtlas(
 ): BaseCharAtlas {
   const newConfig = generateConfig(scaledCharWidth, scaledCharHeight, terminal, colors);
 
-  // TODO: Currently if a terminal changes configs it will not free the entry reference (until it's disposed)
-
   // Check to see if the terminal already owns this config
   for (let i = 0; i < charAtlasCache.length; i++) {
     const entry = charAtlasCache[i];
@@ -54,6 +52,7 @@ export function acquireCharAtlas(
       }
       // The configs differ, release the terminal from the entry
       if (entry.ownedBy.length === 1) {
+        entry.atlas.dispose();
         charAtlasCache.splice(i, 1);
       } else {
         entry.ownedBy.splice(ownedByIndex, 1);
@@ -94,6 +93,7 @@ export function removeTerminalFromCache(terminal: ITerminal): void {
     if (index !== -1) {
       if (charAtlasCache[i].ownedBy.length === 1) {
         // Remove the cache entry if it's the only terminal
+        charAtlasCache[i].atlas.dispose();
         charAtlasCache.splice(i, 1);
       } else {
         // Remove the reference from the cache entry
diff --git a/src/utils/MouseHelper.test.ts b/src/ui/MouseHelper.test.ts
similarity index 61%
rename from src/utils/MouseHelper.test.ts
rename to src/ui/MouseHelper.test.ts
index 94d63b2b..26888bf7 100644
--- a/src/utils/MouseHelper.test.ts
+++ b/src/ui/MouseHelper.test.ts
@@ -37,34 +37,28 @@ describe('MouseHelper.getCoords', () => {
   describe('when charMeasure is not initialized', () => {
     it('should return null', () => {
       charMeasure = new MockCharMeasure();
-      assert.equal(mouseHelper.getCoords({ pageX: 0, pageY: 0 }, document.createElement('div'), charMeasure, 10, 10), null);
-    });
-  });
-
-  describe('when pageX/pageY are not supported', () => {
-    it('should return null', () => {
-      assert.equal(mouseHelper.getCoords({ pageX: undefined, pageY: undefined }, document.createElement('div'), charMeasure, 10, 10), null);
+      assert.equal(mouseHelper.getCoords({ clientX: 0, clientY: 0 }, document.createElement('div'), charMeasure, 10, 10), null);
     });
   });
 
   it('should return the cell that was clicked', () => {
     let coords: [number, number];
-    coords = mouseHelper.getCoords({ pageX: CHAR_WIDTH / 2, pageY: CHAR_HEIGHT / 2 }, document.createElement('div'), charMeasure, 10, 10);
+    coords = mouseHelper.getCoords({ clientX: CHAR_WIDTH / 2, clientY: CHAR_HEIGHT / 2 }, document.createElement('div'), charMeasure, 10, 10);
     assert.deepEqual(coords, [1, 1]);
-    coords = mouseHelper.getCoords({ pageX: CHAR_WIDTH, pageY: CHAR_HEIGHT }, document.createElement('div'), charMeasure, 10, 10);
+    coords = mouseHelper.getCoords({ clientX: CHAR_WIDTH, clientY: CHAR_HEIGHT }, document.createElement('div'), charMeasure, 10, 10);
     assert.deepEqual(coords, [1, 1]);
-    coords = mouseHelper.getCoords({ pageX: CHAR_WIDTH, pageY: CHAR_HEIGHT + 1 }, document.createElement('div'), charMeasure, 10, 10);
+    coords = mouseHelper.getCoords({ clientX: CHAR_WIDTH, clientY: CHAR_HEIGHT + 1 }, document.createElement('div'), charMeasure, 10, 10);
     assert.deepEqual(coords, [1, 2]);
-    coords = mouseHelper.getCoords({ pageX: CHAR_WIDTH + 1, pageY: CHAR_HEIGHT }, document.createElement('div'), charMeasure, 10, 10);
+    coords = mouseHelper.getCoords({ clientX: CHAR_WIDTH + 1, clientY: CHAR_HEIGHT }, document.createElement('div'), charMeasure, 10, 10);
     assert.deepEqual(coords, [2, 1]);
   });
 
   it('should ensure the coordinates are returned within the terminal bounds', () => {
     let coords: [number, number];
-    coords = mouseHelper.getCoords({ pageX: -1, pageY: -1 }, document.createElement('div'), charMeasure, 10, 10);
+    coords = mouseHelper.getCoords({ clientX: -1, clientY: -1 }, document.createElement('div'), charMeasure, 10, 10);
     assert.deepEqual(coords, [1, 1]);
     // Event are double the cols/rows
-    coords = mouseHelper.getCoords({ pageX: CHAR_WIDTH * 20, pageY: CHAR_HEIGHT * 20 }, document.createElement('div'), charMeasure, 10, 10);
+    coords = mouseHelper.getCoords({ clientX: CHAR_WIDTH * 20, clientY: CHAR_HEIGHT * 20 }, document.createElement('div'), charMeasure, 10, 10);
     assert.deepEqual(coords, [10, 10], 'coordinates should never come back as larger than the terminal');
   });
 });
diff --git a/src/utils/MouseHelper.ts b/src/ui/MouseHelper.ts
similarity index 72%
rename from src/utils/MouseHelper.ts
rename to src/ui/MouseHelper.ts
index e4b3f211..e36e7f17 100644
--- a/src/utils/MouseHelper.ts
+++ b/src/ui/MouseHelper.ts
@@ -3,40 +3,19 @@
  * @license MIT
  */
 
-import { ICharMeasure } from '../Types';
+import { ICharMeasure, IMouseHelper } from '../Types';
 import { IRenderer } from '../renderer/Types';
 
-export class MouseHelper {
+export class MouseHelper implements IMouseHelper {
   constructor(private _renderer: IRenderer) {}
 
   public setRenderer(renderer: IRenderer): void {
     this._renderer = renderer;
   }
 
-  public static getCoordsRelativeToElement(event: {pageX: number, pageY: number}, element: HTMLElement): [number, number] {
-    // Ignore browsers that don't support MouseEvent.pageX
-    if (event.pageX === null || event.pageX === undefined) {
-      return null;
-    }
-
-    const originalElement = element;
-    let x = event.pageX;
-    let y = event.pageY;
-
-    // Converts the coordinates from being relative to the document to being
-    // relative to the terminal.
-    while (element) {
-      x -= element.offsetLeft;
-      y -= element.offsetTop;
-      element = <HTMLElement>element.offsetParent;
-    }
-    element = originalElement;
-    while (element && element !== element.ownerDocument.body) {
-      x += element.scrollLeft;
-      y += element.scrollTop;
-      element = <HTMLElement>element.parentElement;
-    }
-    return [x, y];
+  public static getCoordsRelativeToElement(event: {clientX: number, clientY: number}, element: HTMLElement): [number, number] {
+    const rect = element.getBoundingClientRect();
+    return [event.clientX - rect.left, event.clientY - rect.top];
   }
 
   /**
@@ -52,7 +31,7 @@ export class MouseHelper {
    * apply an offset to the x value such that the left half of the cell will
    * select that cell and the right half will select the next cell.
    */
-  public getCoords(event: {pageX: number, pageY: number}, element: HTMLElement, charMeasure: ICharMeasure, colCount: number, rowCount: number, isSelection?: boolean): [number, number] {
+  public getCoords(event: {clientX: number, clientY: number}, element: HTMLElement, charMeasure: ICharMeasure, colCount: number, rowCount: number, isSelection?: boolean): [number, number] {
     // Coordinates cannot be measured if charMeasure has not been initialized
     if (!charMeasure.width || !charMeasure.height) {
       return null;
diff --git a/src/utils/TestUtils.test.ts b/src/ui/TestUtils.test.ts
similarity index 100%
rename from src/utils/TestUtils.test.ts
rename to src/ui/TestUtils.test.ts