Detect full screen exit properly and use :fullscreen style instead of custom class to get black background.

src/styles/components/_audiovideo.scss

@@ -34,7 +34,6 @@
   }
 
   &.fullscreen {
-    background: #000 !important;
     bottom: 0 !important;
     left: 0 !important;
     right: 0 !important;

src/styles/global/_base.scss

@@ -65,3 +65,7 @@ a {
 .desktopnotify-icon {
   background-image: url('../img/logo-48x48.png');
 }
+
+:fullscreen {
+  background: #000;
+}

static/js/directives/audiovideo.js

@@ -216,8 +216,13 @@ define(['jquery', 'underscore', 'text!partials/audiovideo.html', 'text!partials/
 			$scope.toggleFullscreen = function() {
 				//console.log("Toggle full screen", BigScreen.enabled, $scope.isActive, $scope.hasUsermedia);
 				if (BigScreen.enabled && ($scope.isActive || $scope.hasUsermedia)) {
-					$scope.layoutparent.toggleClass("fullscreen");
-					BigScreen.toggle($scope.layoutparent[0]);
+					BigScreen.toggle($scope.layoutparent[0], function() {
+						// onEnter
+						$scope.layoutparent.addClass("fullscreen");
+					}, function() {
+						// onExit
+						$scope.layoutparent.removeClass("fullscreen");
+					});
 				}
 			};