diff --git a/ext/src/background/castManager.ts b/ext/src/background/castManager.ts
index 14599a6..c2980a2 100644
--- a/ext/src/background/castManager.ts
+++ b/ext/src/background/castManager.ts
@@ -20,6 +20,7 @@ import {
 
 import type { ApiConfig } from "../cast/sdk/classes";
 import { ReceiverAction } from "../cast/sdk/enums";
+import { DEFAULT_MEDIA_RECEIVER_APP_ID } from "../cast/sdk/media";
 import { createReceiver } from "../cast/utils";
 
 import deviceManager from "./deviceManager";
@@ -301,10 +302,10 @@ const castManager = new (class {
                 if (
                     receiverSelector?.isOpen &&
                     // If selector context is the same as the instance context
-                    receiverSelector.pageInfo?.tabId ===
-                        instance.contentContext?.tabId &&
-                    receiverSelector.pageInfo?.frameId ===
-                        instance.contentContext?.frameId &&
+                    isSameContext(
+                        receiverSelector.pageInfo,
+                        instance.contentContext
+                    ) &&
                     // If selector is supposed to close
                     (await options.get("receiverSelectorWaitForConnection"))
                 ) {
@@ -566,17 +567,48 @@ async function getReceiverSelection(selectionOpts: {
     let availableMediaTypes = ReceiverSelectorMediaType.None;
 
     // Default frame ID
-    if (!selectionOpts.frameId) selectionOpts.frameId = 0;
+    if (selectionOpts.frameId === undefined) selectionOpts.frameId = 0;
 
     // Fallback to instance context
-    if (!selectionOpts.tabId && selectionOpts.castInstance?.contentContext) {
+    if (
+        selectionOpts.tabId === undefined &&
+        selectionOpts.castInstance?.contentContext
+    ) {
         selectionOpts.tabId = selectionOpts.castInstance.contentContext.tabId;
         selectionOpts.frameId =
             selectionOpts.castInstance.contentContext.frameId;
     }
 
+    const opts = await options.getAll();
+
+    /**
+     * If context supplied, but no instance, check for an instance at
+     * that context.
+     */
+    if (
+        !selectionOpts.castInstance &&
+        selectionOpts.tabId !== undefined &&
+        selectionOpts.frameId !== undefined
+    ) {
+        const contextInstance = castManager.getInstanceAt(
+            selectionOpts.tabId,
+            selectionOpts.frameId
+        );
+        /**
+         * If the app in that context is the extension mirroring app or
+         * the default receiver, just ignore it.
+         */
+        const contextAppId = contextInstance?.apiConfig?.sessionRequest.appId;
+        if (
+            contextAppId !== opts.mirroringAppId &&
+            contextAppId !== DEFAULT_MEDIA_RECEIVER_APP_ID
+        ) {
+            selectionOpts.castInstance = contextInstance;
+        }
+    }
+
     let pageInfo: Optional<ReceiverSelectorPageInfo>;
-    if (selectionOpts.tabId) {
+    if (selectionOpts.tabId !== undefined) {
         try {
             pageInfo = {
                 tabId: selectionOpts.tabId,
@@ -603,8 +635,6 @@ async function getReceiverSelection(selectionOpts: {
         availableMediaTypes |= ReceiverSelectorMediaType.App;
     }
 
-    const opts = await options.getAll();
-
     // Disable mirroring media types if mirroring is not enabled
     if (!opts.mirroringEnabled) {
         availableMediaTypes &= ~(
diff --git a/ext/src/cast/senders/media.ts b/ext/src/cast/senders/media.ts
index 12265ad..01d4efd 100644
--- a/ext/src/cast/senders/media.ts
+++ b/ext/src/cast/senders/media.ts
@@ -5,10 +5,10 @@ import type { Message } from "../../messaging";
 
 // Cast types
 import { Capability, ReceiverAvailability } from "../sdk/enums";
+import { Media, PlayerState } from "../sdk/media";
 import type Session from "../sdk/Session";
 
 import cast, { ensureInit, CastPort } from "../export";
-import { Media, PlayerState } from "../sdk/media";
 
 const logger = new Logger("fx_cast [media sender]");
 
diff --git a/ext/src/cast/senders/mirroring.ts b/ext/src/cast/senders/mirroring.ts
index b2237b8..9e3be18 100644
--- a/ext/src/cast/senders/mirroring.ts
+++ b/ext/src/cast/senders/mirroring.ts
@@ -5,9 +5,10 @@ import { Logger } from "../../lib/logger";
 
 import { ReceiverDevice, ReceiverSelectorMediaType } from "../../types";
 
-import type Session from "../sdk/Session";
-import cast, { ensureInit } from "../export";
 import type { ReceiverAvailability } from "../sdk/enums";
+import type Session from "../sdk/Session";
+
+import cast, { ensureInit } from "../export";
 
 const logger = new Logger("fx_cast [mirroring sender]");
 
@@ -49,7 +50,7 @@ class MirroringSender {
 
     private async init() {
         try {
-            ensureInit({
+            await ensureInit({
                 contextTabId: this.contextTabId,
                 receiverDevice: this.receiverDevice
             });
diff --git a/ext/src/ui/popup/Popup.svelte b/ext/src/ui/popup/Popup.svelte
index adb473a..a54e6ce 100644
--- a/ext/src/ui/popup/Popup.svelte
+++ b/ext/src/ui/popup/Popup.svelte
@@ -67,19 +67,37 @@
      * Checks if device is compatible with the requested app and
      * capabilities.
      */
-    function isDeviceCompatible(device: ReceiverDevice) {
-        // If device is audio-only, check app's audio support flag
-        if (
-            !(device.capabilities & ReceiverDeviceCapabilities.VIDEO_OUT) &&
-            appInfo?.isRequestAppAudioCompatible === false
-        ) {
-            return false;
+    function isDeviceCompatible(
+        mediaType: ReceiverSelectorMediaType,
+        device: ReceiverDevice
+    ) {
+        switch (mediaType) {
+            case ReceiverSelectorMediaType.App:
+                // If device is audio-only, check app's audio support flag
+                if (
+                    !(
+                        device.capabilities &
+                        ReceiverDeviceCapabilities.VIDEO_OUT
+                    ) &&
+                    appInfo?.isRequestAppAudioCompatible === false
+                ) {
+                    return false;
+                }
+
+                return hasRequiredCapabilities(
+                    device,
+                    appInfo?.sessionRequest?.capabilities
+                );
+
+            /** Mirroring requires video output capability. */
+            case ReceiverSelectorMediaType.Tab:
+            case ReceiverSelectorMediaType.Screen:
+                return !!(
+                    device.capabilities & ReceiverDeviceCapabilities.VIDEO_OUT
+                );
         }
 
-        return hasRequiredCapabilities(
-            device,
-            appInfo?.sessionRequest?.capabilities
-        );
+        return false;
     }
 
     let port: Nullable<Port> = null;
@@ -365,7 +383,7 @@
                 {isMediaTypeAvailable}
                 isAnyMediaTypeAvailable={availableMediaTypes !==
                     ReceiverSelectorMediaType.None &&
-                    isDeviceCompatible(device)}
+                    isDeviceCompatible(mediaType, device)}
                 isAnyConnecting={isConnecting}
                 bind:lastMenuShownDeviceId
                 on:cast={ev => onReceiverCast(ev.detail.device)}