diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
index f9f1e80540..e8419d664b 100644
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -5227,6 +5227,9 @@ pref("dom.storageManager.enabled", false);
 // See application preferences for appropriate defaults.
 pref("prompts.authentication_dialog_abuse_limit", 0);
 
+// Whether content handling dialog is window modal
+pref("prompts.content_handling_dialog_modal.enabled", false);
+
 // Whether module scripts (<script type="module">) are enabled for content.
 pref("dom.moduleScripts.enabled", true);
 
diff --git a/toolkit/mozapps/handling/nsContentDispatchChooser.js b/toolkit/mozapps/handling/nsContentDispatchChooser.js
index e02545594c..95111afc1b 100644
--- a/toolkit/mozapps/handling/nsContentDispatchChooser.js
+++ b/toolkit/mozapps/handling/nsContentDispatchChooser.js
@@ -6,9 +6,8 @@ Components.utils.import("resource://gre/modules/XPCOMUtils.jsm");
 
 // Constants
 
-const Cc = Components.classes;
-const Ci = Components.interfaces;
-const Cr = Components.results;
+const {utils: Cu, interfaces: Ci, classes: Cc, results: Cr} = Components;
+Cu.import("resource://gre/modules/Services.jsm");
 
 const CONTENT_HANDLING_URL = "chrome://mozapps/content/handling/dialog.xul";
 const STRINGBUNDLE_URL = "chrome://mozapps/locale/handling/handling.properties";
@@ -64,13 +63,14 @@ nsContentDispatchChooser.prototype =
     params.appendElement(aURI, false);
     params.appendElement(aWindowContext, false);
 
+    var features = "chrome,dialog=yes,resizable,centerscreen";
+    if (Services.prefs.getBoolPref("prompts.content_handling_dialog_modal.enabled")) {
+      features += ",modal";
+    }
+
     var ww = Cc["@mozilla.org/embedcomp/window-watcher;1"].
              getService(Ci.nsIWindowWatcher);
-    ww.openWindow(window,
-                  CONTENT_HANDLING_URL,
-                  null,
-                  "chrome,dialog=yes,resizable,centerscreen",
-                  params);
+    ww.openWindow(window, CONTENT_HANDLING_URL, null, features, params);
   },
 
   // nsISupports