diff --git a/mobile/android/modules/geckoview/GeckoViewModule.jsm b/mobile/android/modules/geckoview/GeckoViewModule.jsm
index 29d0881f0f9e..633ef8189eb2 100644
--- a/mobile/android/modules/geckoview/GeckoViewModule.jsm
+++ b/mobile/android/modules/geckoview/GeckoViewModule.jsm
@@ -129,13 +129,13 @@ class EventProxy {
   }
 
   registerListener(aEventList) {
-    debug("rabbit register " + aEventList);
+    debug("register " + aEventList);
     this.eventDispatcher.registerListener(this, aEventList);
     this._registeredEvents = this._registeredEvents.concat(aEventList);
   }
 
   unregisterListener() {
-    debug("rabbit unregister");
+    debug("unregister");
     if (this._registeredEvents.length === 0) {
       return;
     }
@@ -145,7 +145,7 @@ class EventProxy {
 
   onEvent(aEvent, aData, aCallback) {
     if (this._enableQueuing) {
-      debug("rabbit queue " + aEvent + ", aData=" + JSON.stringify(aData));
+      debug("queue " + aEvent + ", aData=" + JSON.stringify(aData));
       this._eventQueue.unshift(arguments);
     } else {
       this._dispatch.apply(this, arguments);
@@ -158,12 +158,12 @@ class EventProxy {
   }
 
   _dispatch(aEvent, aData, aCallback) {
-    debug("rabbit dispatch " + aEvent + ", aData=" + JSON.stringify(aData));
+    debug("dispatch " + aEvent + ", aData=" + JSON.stringify(aData));
     this.listener.onEvent.apply(this.listener, arguments);
   }
 
   dispatchQueuedEvents() {
-    debug("rabbit dispatchQueued");
+    debug("dispatchQueued");
     while (this._eventQueue.length) {
       const e = this._eventQueue.pop();
       this._dispatch.apply(this, e);
diff --git a/mobile/android/modules/geckoview/GeckoViewNavigation.jsm b/mobile/android/modules/geckoview/GeckoViewNavigation.jsm
index 16e37949b49e..ee23f145f463 100644
--- a/mobile/android/modules/geckoview/GeckoViewNavigation.jsm
+++ b/mobile/android/modules/geckoview/GeckoViewNavigation.jsm
@@ -152,9 +152,21 @@ class GeckoViewNavigation extends GeckoViewModule {
           " aWhere=" + aWhere +
           " aFlags=" + aFlags);
 
+    if (LoadURIDelegate.load(this.eventDispatcher, aUri, aWhere, aFlags,
+                             aTriggeringPrincipal)) {
+      // The app has handled the load, abort open-window handling.
+      Components.returnCode = Cr.NS_ERROR_ABORT;
+      return null;
+    }
+
     const browser = this.handleNewSession(aUri, aOpener, aWhere, aFlags,
                                           aTriggeringPrincipal);
-    return browser && browser.contentWindow;
+    if (!browser) {
+      Components.returnCode = Cr.NS_ERROR_ABORT;
+      return null;
+    }
+
+    return browser.contentWindow;
   }
 
   // nsIBrowserDOMWindow.
@@ -167,28 +179,42 @@ class GeckoViewNavigation extends GeckoViewModule {
           " aNextTabParentId=" + aNextTabParentId +
           " aName=" + aName);
 
-    const browser = this.handleNewSession(aUri, null, aWhere, aFlags, null);
-    if (browser) {
-      browser.setAttribute("nextTabParentId", aNextTabParentId);
+    if (LoadURIDelegate.load(this.eventDispatcher, aUri, aWhere, aFlags, null)) {
+      // The app has handled the load, abort open-window handling.
+      Components.returnCode = Cr.NS_ERROR_ABORT;
+      return null;
     }
 
+    const browser = this.handleNewSession(aUri, null, aWhere, aFlags, null);
+    if (!browser) {
+      Components.returnCode = Cr.NS_ERROR_ABORT;
+      return null;
+    }
+
+    browser.setAttribute("nextTabParentId", aNextTabParentId);
     return browser;
   }
 
   handleOpenUri(aUri, aOpener, aWhere, aFlags, aTriggeringPrincipal,
                 aNextTabParentId) {
-    let browser = this.browser;
+    debug("handleOpenUri: aUri=" + (aUri && aUri.spec) +
+          " aWhere=" + aWhere +
+          " aFlags=" + aFlags);
+
     if (LoadURIDelegate.load(this.eventDispatcher, aUri, aWhere, aFlags,
                              aTriggeringPrincipal)) {
-      return browser;
+      return null;
     }
 
+    let browser = this.browser;
+
     if (aWhere === Ci.nsIBrowserDOMWindow.OPEN_NEWWINDOW ||
         aWhere === Ci.nsIBrowserDOMWindow.OPEN_NEWTAB ||
         aWhere === Ci.nsIBrowserDOMWindow.OPEN_SWITCHTAB) {
       browser = this.handleNewSession(aUri, aOpener, aWhere, aFlags,
                                       aTriggeringPrincipal);
     }
+
     if (!browser) {
       // Should we throw?
       return null;