diff --git a/addons/xterm-addon-webgl/src/GlyphRenderer.ts b/addons/xterm-addon-webgl/src/GlyphRenderer.ts
index e679232c..6eff4ced 100644
--- a/addons/xterm-addon-webgl/src/GlyphRenderer.ts
+++ b/addons/xterm-addon-webgl/src/GlyphRenderer.ts
@@ -185,17 +185,15 @@ export class GlyphRenderer  extends Disposable {
       return;
     }
 
-    let rasterizedGlyph: IRasterizedGlyph;
     if (!this._atlas) {
       return;
     }
 
     // Get the glyph
+    let rasterizedGlyph: IRasterizedGlyph;
     if (chars && chars.length > 1) {
-      // TODO: Use actual ext
       rasterizedGlyph = this._atlas.getRasterizedGlyphCombinedChar(chars, bg, fg, ext);
     } else {
-      // TODO: Use actual ext
       rasterizedGlyph = this._atlas.getRasterizedGlyph(code, bg, fg, ext);
     }
 
diff --git a/addons/xterm-addon-webgl/src/RenderModel.ts b/addons/xterm-addon-webgl/src/RenderModel.ts
index b93e1e85..2969a6d1 100644
--- a/addons/xterm-addon-webgl/src/RenderModel.ts
+++ b/addons/xterm-addon-webgl/src/RenderModel.ts
@@ -6,9 +6,10 @@
 import { IRenderModel, ISelectionRenderModel } from './Types';
 import { fill } from 'common/TypedArrayUtils';
 
-export const RENDER_MODEL_INDICIES_PER_CELL = 3;
+export const RENDER_MODEL_INDICIES_PER_CELL = 4;
 export const RENDER_MODEL_BG_OFFSET = 1;
 export const RENDER_MODEL_FG_OFFSET = 2;
+export const RENDER_MODEL_EXT_OFFSET = 3;
 
 export const COMBINED_CHAR_BIT_MASK = 0x80000000;
 
diff --git a/addons/xterm-addon-webgl/src/WebglRenderer.ts b/addons/xterm-addon-webgl/src/WebglRenderer.ts
index 7790b8c2..904e8d5a 100644
--- a/addons/xterm-addon-webgl/src/WebglRenderer.ts
+++ b/addons/xterm-addon-webgl/src/WebglRenderer.ts
@@ -10,9 +10,9 @@ import { acquireCharAtlas } from './atlas/CharAtlasCache';
 import { WebglCharAtlas } from './atlas/WebglCharAtlas';
 import { RectangleRenderer } from './RectangleRenderer';
 import { IWebGL2RenderingContext } from './Types';
-import { RenderModel, COMBINED_CHAR_BIT_MASK, RENDER_MODEL_BG_OFFSET, RENDER_MODEL_FG_OFFSET, RENDER_MODEL_INDICIES_PER_CELL } from './RenderModel';
+import { RenderModel, COMBINED_CHAR_BIT_MASK, RENDER_MODEL_BG_OFFSET, RENDER_MODEL_FG_OFFSET, RENDER_MODEL_EXT_OFFSET, RENDER_MODEL_INDICIES_PER_CELL } from './RenderModel';
 import { Disposable } from 'common/Lifecycle';
-import { Attributes, Content, FgFlags, NULL_CELL_CHAR, NULL_CELL_CODE } from 'common/buffer/Constants';
+import { Attributes, BgFlags, Content, FgFlags, NULL_CELL_CHAR, NULL_CELL_CODE } from 'common/buffer/Constants';
 import { Terminal, IEvent } from 'xterm';
 import { IRenderLayer } from './renderLayer/Types';
 import { IRenderDimensions, IRenderer, IRequestRedrawEvent } from 'browser/renderer/Types';
@@ -343,7 +343,8 @@ export class WebglRenderer extends Disposable implements IRenderer {
         // Nothing has changed, no updates needed
         if (this._model.cells[i] === code &&
             this._model.cells[i + RENDER_MODEL_BG_OFFSET] === this._workColors.bg &&
-            this._model.cells[i + RENDER_MODEL_FG_OFFSET] === this._workColors.fg) {
+            this._model.cells[i + RENDER_MODEL_FG_OFFSET] === this._workColors.fg &&
+            this._model.cells[i + RENDER_MODEL_EXT_OFFSET] === this._workColors.ext) {
           continue;
         }
 
@@ -356,6 +357,7 @@ export class WebglRenderer extends Disposable implements IRenderer {
         this._model.cells[i] = code;
         this._model.cells[i + RENDER_MODEL_BG_OFFSET] = this._workColors.bg;
         this._model.cells[i + RENDER_MODEL_FG_OFFSET] = this._workColors.fg;
+        this._model.cells[i + RENDER_MODEL_EXT_OFFSET] = this._workColors.ext;
 
         this._glyphRenderer.updateCell(x, y, code, this._workColors.bg, this._workColors.fg, this._workColors.ext, chars, lastBg);
 
@@ -370,6 +372,7 @@ export class WebglRenderer extends Disposable implements IRenderer {
             this._model.cells[j] = NULL_CELL_CODE;
             this._model.cells[j + RENDER_MODEL_BG_OFFSET] = this._workColors.bg;
             this._model.cells[j + RENDER_MODEL_FG_OFFSET] = this._workColors.fg;
+            this._model.cells[j + RENDER_MODEL_EXT_OFFSET] = this._workColors.ext;
           }
         }
       }
@@ -384,8 +387,7 @@ export class WebglRenderer extends Disposable implements IRenderer {
   private _loadColorsForCell(x: number, y: number): void {
     this._workColors.bg = this._workCell.bg;
     this._workColors.fg = this._workCell.fg;
-    this._workColors.ext = this._workCell.extended.ext;
-
+    this._workColors.ext = this._workCell.bg & BgFlags.HAS_EXTENDED ? this._workCell.extended.ext : 0;
     // Get any foreground/background overrides, this happens on the model to avoid spreading
     // override logic throughout the different sub-renderers
     let bgOverride: number | undefined;
diff --git a/addons/xterm-addon-webgl/src/atlas/WebglCharAtlas.ts b/addons/xterm-addon-webgl/src/atlas/WebglCharAtlas.ts
index 1e7d7eda..8638eec1 100644
--- a/addons/xterm-addon-webgl/src/atlas/WebglCharAtlas.ts
+++ b/addons/xterm-addon-webgl/src/atlas/WebglCharAtlas.ts
@@ -160,7 +160,7 @@ export class WebglCharAtlas implements IDisposable {
     let rasterizedGlyphSet = cacheMap[key];
     if (!rasterizedGlyphSet) {
       rasterizedGlyphSet = {};
-      this._cacheMapCombined[key] = rasterizedGlyphSet;
+      cacheMap[key] = rasterizedGlyphSet;
     }
 
     let rasterizedGlyphSetBg = rasterizedGlyphSet[bg];
diff --git a/demo/client.ts b/demo/client.ts
index 4098c775..f8fa7eb5 100644
--- a/demo/client.ts
+++ b/demo/client.ts
@@ -210,6 +210,9 @@ function createTerminal(): void {
   term.open(terminalContainer);
   addons.fit.instance!.fit();
   typedTerm.loadAddon(addons.webgl.instance);
+  setTimeout(() => {
+    document.body.appendChild(addons.webgl.instance.textureAtlas);
+  }, 0);
   term.focus();
 
   addDomListener(paddingElement, 'change', setPadding);