Make the full screen plugin work again

editions/tw5.com/tiddlers/Features.tid

@@ -13,6 +13,7 @@ title: Features
 * Familiar user interface elements like <$button message="tw-modal" param="SampleWizard" class="btn btn-inverse">wizards</$button> and <$button message="tw-notify" param="SampleNotification" class="btn btn-inverse">notifications</$button>
 * Easily [[import|ImportTiddlers]] content via drag and drop, copy and paste, or browsing for local files 
 * TiddlyWiki is [[surprisingly scalable|Scalability]] to many thousands of tiddlers and megabytes of content
+* Try out the <$button message="tw-full-screen">full screen support</$button>
 * Explore the [[D3.js visualisation plugin|http://five.tiddlywiki.com/d3demo.html]]
 * Try out the [[CodeMirror plugin|http://five.tiddlywiki.com/codemirrordemo.html]]
 * Many internal improvements:

plugins/tiddlywiki/fullscreen/init.js

@@ -22,9 +22,9 @@ var toggleFullScreen = function() {
 
 exports.startup = function() {
 	// Install the full screen handler
-	document.addEventListener("tw-full-screen",function(event) {
+	$tw.rootWidget.addEventListener("tw-full-screen",function(event) {
 		toggleFullScreen();
-	},false);
+	});
 };
 
 })();