diff --git a/static/js/directives/screenshare.js b/static/js/directives/screenshare.js
index 0eb8ae12..6a060ba9 100644
--- a/static/js/directives/screenshare.js
+++ b/static/js/directives/screenshare.js
@@ -281,7 +281,10 @@ define(['jquery', 'underscore', 'text!partials/screenshare.html', 'text!partials
 					console.log("Screen share stopped.");
 				}
 
-				$scope.layout.screenshare = false;
+				if ($scope.layout.screenshare) {
+					screensharing.cancelGetScreen();
+					$scope.layout.screenshare = false;
+				}
 
 			};
 
@@ -297,6 +300,10 @@ define(['jquery', 'underscore', 'text!partials/screenshare.html', 'text!partials
 
 			};
 
+			mediaStream.webrtc.e.on("done", function() {
+				$scope.stopScreenshare();
+			});
+
 			$scope.$watch("layout.screenshare", function(newval, oldval) {
 				if (newval && !oldval) {
 					$scope.doScreenshare();
diff --git a/static/js/services/chromeextension.js b/static/js/services/chromeextension.js
index 532c8909..2853d743 100644
--- a/static/js/services/chromeextension.js
+++ b/static/js/services/chromeextension.js
@@ -54,14 +54,22 @@ define(["underscore"], function(_) {
 			case "Call":
 				var deferred = this.registry[data.n];
 				if (deferred) {
-					delete this.registry[data.n];
 					var call = data.Call;
-					if (call.Type === "Result") {
+					switch (call.Type) {
+					case "Result":
+						delete this.registry[data.n];
 						//console.log("Call complete with result", call);
 						deferred.resolve(call.Result);
-					} else {
+						break;
+					case "Notify":
+						//console.log("Notify", call);
+						deferred.notify(call.Notify);
+						break;
+					case "Error":
+						delete this.registry[data.n];
 						//console.log("Call failed with error", call);
 						deferred.reject(call.Error);
+						break
 					}
 				} else {
 					console.warn("Unknown call reference received", data, this.registry, this);
@@ -80,7 +88,7 @@ define(["underscore"], function(_) {
 			$window.addEventListener("message", function(event) {
 				//console.log("message", event.origin, event.source === window, event);
 				if (event.source === window && event.data.answer) {
-					// Only let through our own messages marked as answer.
+					// Only process answers to avoid loops.
 					extension.onMessage(event);
 				}
 			});
diff --git a/static/js/services/screensharing.js b/static/js/services/screensharing.js
index 1c0341b0..2a7450fd 100644
--- a/static/js/services/screensharing.js
+++ b/static/js/services/screensharing.js
@@ -25,7 +25,12 @@ define(['underscore', 'webrtc.adapter'], function(_) {
 
 		// Check if we can do screensharing.
 		var supported = false;
+
+		// Define our helpers.
 		var prepare = null;
+		var cancel = null;
+
+		// Chrome support.
 		if ($window.webrtcDetectedBrowser === "chrome") {
 			if ($window.webrtcDetectedVersion >= 32 &&
 				$window.webrtcDetectedVersion < 37) {
@@ -52,6 +57,7 @@ define(['underscore', 'webrtc.adapter'], function(_) {
 
 			if (chromeExtension.available) {
 				supported = true;
+				var pending = null;
 				prepare = function(options) {
 					var select = chromeExtension.call({
 						Type: "Action",
@@ -59,7 +65,8 @@ define(['underscore', 'webrtc.adapter'], function(_) {
 					});
 					var d = $q.defer();
 					select.then(function(id) {
-						//console.log("Prepare screensharing success", id);
+						// Success with id.
+						pending = null;
 						if (id) {
 							var opts = _.extend({
 								chromeMediaSource: "desktop",
@@ -70,15 +77,30 @@ define(['underscore', 'webrtc.adapter'], function(_) {
 							d.resolve(null);
 						}
 					}, function(err) {
+						// Error.
+						pending = null;
 						console.log("Failed to prepare screensharing", err);
 						d.reject(err);
+					}, function(data) {
+						// Notify.
+						pending = data;
 					});
 					return d.promise;
 				};
+				cancel = function() {
+					if (pending !== null) {
+						chromeExtension.call({
+							Type: "Action",
+							Action: "cancelChooseDesktopMedia",
+							Args: pending
+						});
+						pending = null;
+					}
+				};
 			}
 
 		} else {
-			// Currently Chrome only.
+			// Currently Chrome only - sorry.
 		}
 
 		// public API.
@@ -92,6 +114,11 @@ define(['underscore', 'webrtc.adapter'], function(_) {
 					d.reject("No implementation to get screen.");
 					return d.promise;
 				}
+			},
+			cancelGetScreen: function() {
+				if (cancel) {
+					cancel();
+				}
 			}
 		}