diff --git a/browser/devtools/webide/content/webide.js b/browser/devtools/webide/content/webide.js
index 04ebb37c950..4b996fdd21e 100644
--- a/browser/devtools/webide/content/webide.js
+++ b/browser/devtools/webide/content/webide.js
@@ -138,6 +138,8 @@ let UI = {
         this.updateProjectButton();
         this.updateProjectEditorHeader();
         break;
+      case "install-progress":
+        this.updateProgress(Math.round(100 * details.bytesSent / details.totalBytes));
     };
   },
 
@@ -169,34 +171,71 @@ let UI = {
     }
   },
 
+  /********** BUSY UI **********/
+
+  _busyTimeout: null,
+  _busyOperationDescription: null,
+  _busyPromise: null,
+
+  updateProgress: function(percent) {
+    let progress = document.querySelector("#action-busy-determined");
+    progress.mode = "determined";
+    progress.value = percent;
+    this.setupBusyTimeout();
+  },
+
   busy: function() {
     this.hidePanels();
-    document.querySelector("window").classList.add("busy")
+    let win = document.querySelector("window");
+    win.classList.add("busy")
+    win.classList.add("busy-undetermined");
     this.updateCommands();
   },
 
   unbusy: function() {
-    document.querySelector("window").classList.remove("busy")
+    let win = document.querySelector("window");
+    win.classList.remove("busy")
+    win.classList.remove("busy-determined");
+    win.classList.remove("busy-undetermined");
     this.updateCommands();
     this._busyPromise = null;
   },
 
+  setupBusyTimeout: function() {
+    this.cancelBusyTimeout();
+    this._busyTimeout = setTimeout(() => {
+      this.unbusy();
+      UI.reportError("error_operationTimeout", this._busyOperationDescription);
+      this._busyPromise.reject("promise timeout: " + this._busyOperationDescription);
+    }, 30000);
+  },
+
+  cancelBusyTimeout: function() {
+    clearTimeout(this._busyTimeout);
+  },
+
+  busyWithProgressUntil: function(promise, operationDescription) {
+    this.busyUntil(promise, operationDescription);
+    let win = document.querySelector("window");
+    let progress = document.querySelector("#action-busy-determined");
+    progress.mode = "undetermined";
+    win.classList.add("busy-determined");
+    win.classList.remove("busy-undetermined");
+  },
+
   busyUntil: function(promise, operationDescription) {
     // Freeze the UI until the promise is resolved. A 30s timeout
     // will unfreeze the UI, just in case the promise never gets
     // resolved.
     this._busyPromise = promise;
-    let timeout = setTimeout(() => {
-      this.unbusy();
-      UI.reportError("error_operationTimeout", operationDescription);
-      promise.reject("promise timeout: " + operationDescription);
-    }, 30000);
+    this._busyOperationDescription = operationDescription;
+    this.setupBusyTimeout();
     this.busy();
     promise.then(() => {
-      clearTimeout(timeout);
+      this.cancelBusyTimeout();
       this.unbusy();
     }, (e) => {
-      clearTimeout(timeout);
+      this.cancelBusyTimeout();
       UI.reportError("error_operationFail", operationDescription);
       console.error(e);
       this.unbusy();
@@ -396,6 +435,12 @@ let UI = {
       return;
     }
 
+    // Save last project location
+
+    if (project.location) {
+      Services.prefs.setCharPref("devtools.webide.lastprojectlocation", project.location);
+    }
+
     // Make sure the directory exist before we show Project Editor
 
     let forceDetailsOnly = false;
@@ -420,10 +465,6 @@ let UI = {
     this.getProjectEditor().then(() => {
       this.updateProjectEditorHeader();
     }, console.error);
-
-    if (project.location) {
-      Services.prefs.setCharPref("devtools.webide.lastprojectlocation", project.location);
-    }
   },
 
   /********** DECK **********/
@@ -823,12 +864,11 @@ let Cmds = {
   play: function() {
     switch(AppManager.selectedProject.type) {
       case "packaged":
+        return UI.busyWithProgressUntil(AppManager.installAndRunProject(), "installing and running app");
       case "hosted":
         return UI.busyUntil(AppManager.installAndRunProject(), "installing and running app");
-        break;
       case "runtimeApp":
         return UI.busyUntil(AppManager.runRuntimeApp(), "running app");
-        break;
     }
     return promise.reject();
   },
diff --git a/browser/devtools/webide/content/webide.xul b/browser/devtools/webide/content/webide.xul
index 16cac8db20f..ec31544858b 100644
--- a/browser/devtools/webide/content/webide.xul
+++ b/browser/devtools/webide/content/webide.xul
@@ -102,7 +102,10 @@
         <toolbarbutton id="action-button-play"  class="action-button" command="cmd_play" tooltiptext="&projectMenu_play_label;"/>
         <toolbarbutton id="action-button-stop"  class="action-button" command="cmd_stop" tooltiptext="&projectMenu_stop_label;"/>
         <toolbarbutton id="action-button-debug" class="action-button" command="cmd_toggleToolbox" tooltiptext="&projectMenu_debug_label;"/>
-        <html:img id="action-busy" src="chrome://webide/skin/throbber.svg"/>
+        <hbox id="action-busy" align="center">
+          <html:img id="action-busy-undetermined" src="chrome://webide/skin/throbber.svg"/>
+          <progressmeter id="action-busy-determined"/>
+        </hbox>
       </hbox>
 
       <hbox id="panel-buttons-container">
diff --git a/browser/devtools/webide/modules/app-manager.js b/browser/devtools/webide/modules/app-manager.js
index a82a1d2fc53..a62b8668a69 100644
--- a/browser/devtools/webide/modules/app-manager.js
+++ b/browser/devtools/webide/modules/app-manager.js
@@ -59,11 +59,15 @@ exports.AppManager = AppManager = {
     this.trackWiFiRuntimes();
     this.trackSimulatorRuntimes();
 
+    this.onInstallProgress = this.onInstallProgress.bind(this);
+    AppActorFront.on("install-progress", this.onInstallProgress);
+
     this.observe = this.observe.bind(this);
     Services.prefs.addObserver(WIFI_SCANNING_PREF, this, false);
   },
 
   uninit: function() {
+    AppActorFront.off("install-progress", this.onInstallProgress);
     this._unlistenToApps();
     this.selectedProject = null;
     this.selectedRuntime = null;
@@ -134,6 +138,10 @@ exports.AppManager = AppManager = {
     this.update("connection");
   },
 
+  onInstallProgress: function(event, details) {
+    this.update("install-progress", details);
+  },
+
   onWebAppsStoreready: function() {
     this.update("runtime-apps-found");
   },
diff --git a/browser/devtools/webide/themes/webide.css b/browser/devtools/webide/themes/webide.css
index ef876951957..fe16b3a8849 100644
--- a/browser/devtools/webide/themes/webide.css
+++ b/browser/devtools/webide/themes/webide.css
@@ -21,13 +21,15 @@
   pointer-events: auto;
 }
 
-#action-busy {
+#action-busy-undetermined {
   height: 24px;
   width: 24px;
 }
 
 window.busy .action-button,
-window:not(.busy) #action-busy {
+window:not(.busy) #action-busy,
+window.busy-undetermined #action-busy-determined,
+window.busy-determined #action-busy-undetermined {
   display: none;
 }