diff --git a/content/treestyletab/res/fullScreenCanvas.xul b/content/treestyletab/res/fullScreenCanvas.xul
index 343980fb..879bca9d 100644
--- a/content/treestyletab/res/fullScreenCanvas.xul
+++ b/content/treestyletab/res/fullScreenCanvas.xul
@@ -19,7 +19,7 @@
 window.addEventListener('DOMContentLoaded', function() {
 	window.removeEventListener('DOMContentLoaded', arguments.callee, true);
 
-	const currentRevision = 6;
+	const currentRevision = 7;
 	var root = document.documentElement;
 
 	var loadedRevision = root.getAttribute('fullScreenCanvas');
diff --git a/content/treestyletab/treestyletabbrowser.js b/content/treestyletab/treestyletabbrowser.js
index 150f7ded..c5af3b53 100644
--- a/content/treestyletab/treestyletabbrowser.js
+++ b/content/treestyletab/treestyletabbrowser.js
@@ -3664,7 +3664,7 @@ TreeStyleTabBrowser.prototype = {
 		var browserBox = this.mTabBrowser.mCurrentBrowser.boxObject;
 		var contentBox = this.getBoxObjectFor(frame.document.documentElement);
 
-		var zoom = window.fullScreenCanvas.getZoomForFrame(frame);
+		var zoom = fullScreenCanvas.getZoomForFrame(frame);
 
 		var x = (pos == 'right') ? browserBox.width - this.autoHideXOffset : 0 ;
 		var y = (pos == 'bottom') ? browserBox.height - this.autoHideYOffset : 0 ;