--- a/browser/locales/en-US/chrome/browser/browser.properties
+++ b/browser/locales/en-US/chrome/browser/browser.properties
@@ -467,28 +467,32 @@ social.error.message=%1$S is unable to c
 social.error.tryAgain.label=Try Again
 social.error.tryAgain.accesskey=T
 social.error.closeSidebar.label=Close This Sidebar
 social.error.closeSidebar.accesskey=C
 
 # LOCALIZATION NOTE: %1$S is the label for the toolbar button, %2$S is the associated badge numbering that the social provider may provide.
 social.aria.toolbarButtonBadgeText=%1$S (%2$S)
 
-# LOCALIZATION NOTE (getUserMedia.shareCamera2.message, getUserMedia.shareMicrophone2.message,
-#                    getUserMedia.shareScreen2.message, getUserMedia.shareCameraAndMicrophone2.message,
-#                    getUserMedia.shareScreenAndMicrophone2.message, getUserMedia.shareCameraAndAudioCapture2.message,
-#                    getUserMedia.shareAudioCapture2.message, getUserMedia.shareScreenAndAudioCapture2.message):
-#  %S is the website origin (e.g. www.mozilla.org)
+# LOCALIZATION NOTE (getUserMedia.shareCamera2.message,
+#                    getUserMedia.shareMicrophone2.message,
+#                    getUserMedia.shareScreen3.message,
+#                    getUserMedia.shareCameraAndMicrophone2.message,
+#                    getUserMedia.shareCameraAndAudioCapture2.message,
+#                    getUserMedia.shareScreenAndMicrophone3.message,
+#                    getUserMedia.shareScreenAndAudioCapture3.message,
+#                    getUserMedia.shareAudioCapture2.message):
+# %S is the website origin (e.g. www.mozilla.org)
 getUserMedia.shareCamera2.message = Will you allow %S to use your camera?
 getUserMedia.shareMicrophone2.message = Will you allow %S to use your microphone?
-getUserMedia.shareScreen2.message = Will you allow %S to see your screen or application window?
+getUserMedia.shareScreen3.message = Will you allow %S to see your screen?
 getUserMedia.shareCameraAndMicrophone2.message = Will you allow %S to use your camera and microphone?
 getUserMedia.shareCameraAndAudioCapture2.message = Will you allow %S to use your camera and listen to this tab’s audio?
-getUserMedia.shareScreenAndMicrophone2.message = Will you allow %S to use your microphone and see your screen or application window?
-getUserMedia.shareScreenAndAudioCapture2.message = Will you allow %S to listen to this tab’s audio and see your screen or application window?
+getUserMedia.shareScreenAndMicrophone3.message = Will you allow %S to use your microphone and see your screen?
+getUserMedia.shareScreenAndAudioCapture3.message = Will you allow %S to listen to this tab’s audio and see your screen?
 getUserMedia.shareAudioCapture2.message = Will you allow %S to listen to this tab’s audio?
 # LOCALIZATION NOTE (getUserMedia.shareScreenWarning.message): NB: inserted via innerHTML, so please don't use <, > or & in this string.
 # %S will be the 'learn more' link
 getUserMedia.shareScreenWarning.message = Only share screens with sites you trust. Sharing can allow deceptive sites to browse as you and steal your private data. %S
 # LOCALIZATION NOTE (getUserMedia.shareFirefoxWarning.message): NB: inserted via innerHTML, so please don't use <, > or & in this string.
 # %1$S is brandShortName (eg. Firefox)
 # %2$S will be the 'learn more' link
 getUserMedia.shareFirefoxWarning.message = Only share %1$S with sites you trust. Sharing can allow deceptive sites to browse as you and steal your private data. %2$S
@@ -509,26 +513,30 @@ getUserMedia.shareEntireScreen.label = E
 # Example: Screen 1, Screen 2,..
 getUserMedia.shareMonitor.label = Screen %S
 # LOCALIZATION NOTE (getUserMedia.shareApplicationWindowCount.label):
 # Semicolon-separated list of plural forms.
 # See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
 # Replacement for #1 is the name of the application.
 # Replacement for #2 is the number of windows currently displayed by the application.
 getUserMedia.shareApplicationWindowCount.label=#1 (#2 window);#1 (#2 windows)
+# LOCALIZATION NOTE (getUserMedia.allow.label,
+#                    getUserMedia.dontAllow.label):
+# These two buttons are the possible answers to the various prompts in the
+# "getUserMedia.share{device}.message" strings.
 getUserMedia.allow.label = Allow
 getUserMedia.allow.accesskey = A
 getUserMedia.dontAllow.label = Don’t Allow
 getUserMedia.dontAllow.accesskey = D
 getUserMedia.remember=Remember this decision
-# LOCALIZATION NOTE (ggetUserMedia.reasonForNoPermanentAllow.screen,
+# LOCALIZATION NOTE (getUserMedia.reasonForNoPermanentAllow.screen2,
 #                    getUserMedia.reasonForNoPermanentAllow.audio,
 #                    getUserMedia.reasonForNoPermanentAllow.insecure):
 # %S is brandShortName
-getUserMedia.reasonForNoPermanentAllow.screen=%S can not allow permanent access to your screen or application without asking which one to share.
+getUserMedia.reasonForNoPermanentAllow.screen2=%S can not allow permanent access to your screen without asking which one to share.
 getUserMedia.reasonForNoPermanentAllow.audio=%S can not allow permanent access to your tab’s audio without asking which tab to share.
 getUserMedia.reasonForNoPermanentAllow.insecure=Your connection to this site is not secure. To protect you, %S will only allow access for this session.
 
 getUserMedia.sharingMenu.label = Tabs sharing devices
 getUserMedia.sharingMenu.accesskey = d
 # LOCALIZATION NOTE (getUserMedia.sharingMenuCamera
 #                    getUserMedia.sharingMenuMicrophone,
 #                    getUserMedia.sharingMenuAudioCapture,

--- a/browser/modules/webrtcUI.jsm
+++ b/browser/modules/webrtcUI.jsm
@@ -328,24 +328,39 @@ function getHost(uri, href) {
       let bundle = Services.strings.createBundle(kBundleURI);
       host = bundle.GetStringFromName("getUserMedia.sharingMenuUnknownHost");
     }
   }
   return host;
 }
 
 function prompt(aBrowser, aRequest) {
-  let {audioDevices: audioDevices, videoDevices: videoDevices,
-       sharingScreen: sharingScreen, sharingAudio: sharingAudio,
-       requestTypes: requestTypes} = aRequest;
+  let { audioDevices, videoDevices, sharingScreen, sharingAudio,
+        requestTypes } = aRequest;
   let uri = Services.io.newURI(aRequest.documentURI);
   let host = getHost(uri);
   let chromeDoc = aBrowser.ownerDocument;
   let stringBundle = chromeDoc.defaultView.gNavigatorBundle;
-  let stringId = "getUserMedia.share" + requestTypes.join("And") + "2.message";
+
+  // Mind the order, because for simplicity we're iterating over the list using
+  // "includes()". This allows the rotation of string identifiers. We list the
+  // full identifiers here so they can be cross-referenced more easily.
+  let stringId = [
+    // Individual request types first.
+    "getUserMedia.shareCamera2.message",
+    "getUserMedia.shareMicrophone2.message",
+    "getUserMedia.shareScreen3.message",
+    "getUserMedia.shareAudioCapture2.message",
+    // Combinations of the above request types last.
+    "getUserMedia.shareCameraAndMicrophone2.message",
+    "getUserMedia.shareCameraAndAudioCapture2.message",
+    "getUserMedia.shareScreenAndMicrophone3.message",
+    "getUserMedia.shareScreenAndAudioCapture3.message",
+  ].find(id => id.includes(requestTypes.join("And")));
+
   let message = stringBundle.getFormattedString(stringId, [host]);
 
   let notification; // Used by action callbacks.
   let mainAction = {
     label: stringBundle.getString("getUserMedia.allow.label"),
     accessKey: stringBundle.getString("getUserMedia.allow.accesskey"),
     // The real callback will be set during the "showing" event. The
     // empty function here is so that PopupNotifications.show doesn't
@@ -372,17 +387,17 @@ function prompt(aBrowser, aRequest) {
 
   let productName = gBrandBundle.GetStringFromName("brandShortName");
 
   // Disable the permanent 'Allow' action if the connection isn't secure, or for
   // screen/audio sharing (because we can't guess which window the user wants to
   // share without prompting).
   let reasonForNoPermanentAllow = "";
   if (sharingScreen) {
-    reasonForNoPermanentAllow = "getUserMedia.reasonForNoPermanentAllow.screen";
+    reasonForNoPermanentAllow = "getUserMedia.reasonForNoPermanentAllow.screen2";
   } else if (sharingAudio) {
     reasonForNoPermanentAllow = "getUserMedia.reasonForNoPermanentAllow.audio";
   } else if (!aRequest.secure) {
     reasonForNoPermanentAllow = "getUserMedia.reasonForNoPermanentAllow.insecure";
   }
 
   let options = {
     persistent: true,