--- a/dom/base/PopupBlocker.cpp
+++ b/dom/base/PopupBlocker.cpp
@@ -282,46 +282,59 @@ PopupBlocker::PopupControlState PopupBlo
             }
             break;
           default:
             break;
         }
       }
       break;
     case eMouseEventClass:
-      if (aEvent->IsTrusted() &&
-          aEvent->AsMouseEvent()->button == WidgetMouseEvent::eLeftButton) {
-        abuse = PopupBlocker::openBlocked;
-        switch (aEvent->mMessage) {
-          case eMouseUp:
-            if (PopupAllowedForEvent("mouseup")) {
-              abuse = PopupBlocker::openControlled;
-            }
-            break;
-          case eMouseDown:
-            if (PopupAllowedForEvent("mousedown")) {
-              abuse = PopupBlocker::openControlled;
-            }
-            break;
-          case eMouseClick:
-            /* Click events get special treatment because of their
-               historical status as a more legitimate event handler. If
-               click popups are enabled in the prefs, clear the popup
-               status completely. */
-            if (PopupAllowedForEvent("click")) {
-              abuse = PopupBlocker::openAllowed;
-            }
-            break;
-          case eMouseDoubleClick:
-            if (PopupAllowedForEvent("dblclick")) {
-              abuse = PopupBlocker::openControlled;
-            }
-            break;
-          default:
-            break;
+      if (aEvent->IsTrusted()) {
+        if (aEvent->AsMouseEvent()->button == WidgetMouseEvent::eLeftButton) {
+          abuse = PopupBlocker::openBlocked;
+          switch (aEvent->mMessage) {
+            case eMouseUp:
+              if (PopupAllowedForEvent("mouseup")) {
+                abuse = PopupBlocker::openControlled;
+              }
+              break;
+            case eMouseDown:
+              if (PopupAllowedForEvent("mousedown")) {
+                abuse = PopupBlocker::openControlled;
+              }
+              break;
+            case eMouseClick:
+              /* Click events get special treatment because of their
+                 historical status as a more legitimate event handler. If
+                 click popups are enabled in the prefs, clear the popup
+                 status completely. */
+              if (PopupAllowedForEvent("click")) {
+                abuse = PopupBlocker::openAllowed;
+              }
+              break;
+            case eMouseDoubleClick:
+              if (PopupAllowedForEvent("dblclick")) {
+                abuse = PopupBlocker::openControlled;
+              }
+              break;
+            default:
+              break;
+          }
+        } else if (aEvent->AsMouseEvent()->button ==
+                   WidgetMouseEvent::eRightButton) {
+          abuse = PopupBlocker::openBlocked;
+          switch (aEvent->mMessage) {
+            case eContextMenu:
+              if (PopupAllowedForEvent("contextmenu")) {
+                abuse = PopupBlocker::openControlled;
+              }
+              break;
+            default:
+              break;
+          }
         }
       }
       break;
     case ePointerEventClass:
       if (aEvent->IsTrusted() &&
           aEvent->AsPointerEvent()->button == WidgetMouseEvent::eLeftButton) {
         switch (aEvent->mMessage) {
           case ePointerUp:

--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -1286,17 +1286,17 @@ pref("dom.disable_window_open_feature.mi
 pref("dom.disable_window_open_feature.status",      true);
 pref("dom.disable_window_showModalDialog",          true);
 
 pref("dom.allow_scripts_to_close_windows",          false);
 
 pref("dom.require_user_interaction_for_beforeunload", true);
 
 pref("dom.popup_maximum",                           20);
-pref("dom.popup_allowed_events", "change click dblclick mouseup pointerup notificationclick reset submit touchend");
+pref("dom.popup_allowed_events", "change click dblclick mouseup pointerup notificationclick reset submit touchend contextmenu");
 
 pref("dom.disable_open_click_delay", 1000);
 pref("dom.serviceWorkers.disable_open_click_delay", 1000);
 
 pref("dom.storage.enabled", true);
 // Whether or not LSNG (Next Generation Local Storage) is enabled.
 // See bug 1510410 for enabling this on Nightly.
 #ifdef NIGHTLY_BUILD