diff --git a/browser/components/preferences/applications.js b/browser/components/preferences/applications.js
index 0ce662165c70..e0073ba8fd0a 100644
--- a/browser/components/preferences/applications.js
+++ b/browser/components/preferences/applications.js
@@ -292,6 +292,14 @@ HandlerInfoWrapper.prototype = {
   },
 
   set preferredAction(aNewValue) {
+    // If the action is to use the plugin,
+    // we must set the preferred action to "save to disk".
+    // But only if it's not currently the preferred action.
+    if ((aNewValue == kActionUsePlugin) &&
+        (this.preferredAction != Ci.nsIHandlerInfo.saveToDisk)) {
+      aNewValue = Ci.nsIHandlerInfo.saveToDisk;
+    }
+
     // We don't modify the preferred action if the new action is to use a plugin
     // because handler info objects don't understand our custom "use plugin"
     // value.  Also, leaving it untouched means that we can automatically revert
@@ -1644,33 +1652,31 @@ var gApplicationsPane = {
     var typeItem = this._list.selectedItem;
     var handlerInfo = this._handledTypes[typeItem.type];
 
-    if (aActionItem.hasAttribute("alwaysAsk")) {
+    let action = parseInt(aActionItem.getAttribute("action"), 10);
+
+    // Set the plugin state if we're enabling or disabling a plugin.
+    if (action == kActionUsePlugin)
+      handlerInfo.enablePluginType();
+    else if (handlerInfo.pluginName && !handlerInfo.isDisabledPluginType)
+      handlerInfo.disablePluginType();
+
+    // Set the preferred application handler.
+    // We leave the existing preferred app in the list when we set
+    // the preferred action to something other than useHelperApp so that
+    // legacy datastores that don't have the preferred app in the list
+    // of possible apps still include the preferred app in the list of apps
+    // the user can choose to handle the type.
+    if (action == Ci.nsIHandlerInfo.useHelperApp)
+      handlerInfo.preferredApplicationHandler = aActionItem.handlerApp;
+
+    // Set the "always ask" flag.
+    if (action == Ci.nsIHandlerInfo.alwaysAsk)
       handlerInfo.alwaysAskBeforeHandling = true;
-    }
-    else if (aActionItem.hasAttribute("action")) {
-      let action = parseInt(aActionItem.getAttribute("action"));
-
-      // Set the plugin state if we're enabling or disabling a plugin.
-      if (action == kActionUsePlugin)
-        handlerInfo.enablePluginType();
-      else if (handlerInfo.pluginName && !handlerInfo.isDisabledPluginType)
-        handlerInfo.disablePluginType();
-
-      // Set the preferred application handler.
-      // We leave the existing preferred app in the list when we set
-      // the preferred action to something other than useHelperApp so that
-      // legacy datastores that don't have the preferred app in the list
-      // of possible apps still include the preferred app in the list of apps
-      // the user can choose to handle the type.
-      if (action == Ci.nsIHandlerInfo.useHelperApp)
-        handlerInfo.preferredApplicationHandler = aActionItem.handlerApp;
-
-      // Set the "always ask" flag.
+    else
       handlerInfo.alwaysAskBeforeHandling = false;
 
-      // Set the preferred action.
-      handlerInfo.preferredAction = action;
-    }
+    // Set the preferred action.
+    handlerInfo.preferredAction = action;
 
     handlerInfo.store();
 
diff --git a/browser/components/preferences/in-content/applications.js b/browser/components/preferences/in-content/applications.js
index d6b4f63666d6..0766a946fd7f 100644
--- a/browser/components/preferences/in-content/applications.js
+++ b/browser/components/preferences/in-content/applications.js
@@ -284,6 +284,14 @@ HandlerInfoWrapper.prototype = {
   },
 
   set preferredAction(aNewValue) {
+    // If the action is to use the plugin,
+    // we must set the preferred action to "save to disk".
+    // But only if it's not currently the preferred action.
+    if ((aNewValue == kActionUsePlugin) &&
+        (this.preferredAction != Ci.nsIHandlerInfo.saveToDisk)) {
+      aNewValue = Ci.nsIHandlerInfo.saveToDisk;
+    }
+
     // We don't modify the preferred action if the new action is to use a plugin
     // because handler info objects don't understand our custom "use plugin"
     // value.  Also, leaving it untouched means that we can automatically revert
@@ -1636,33 +1644,31 @@ var gApplicationsPane = {
     var typeItem = this._list.selectedItem;
     var handlerInfo = this._handledTypes[typeItem.type];
 
-    if (aActionItem.hasAttribute("alwaysAsk")) {
+    let action = parseInt(aActionItem.getAttribute("action"));
+
+    // Set the plugin state if we're enabling or disabling a plugin.
+    if (action == kActionUsePlugin)
+      handlerInfo.enablePluginType();
+    else if (handlerInfo.pluginName && !handlerInfo.isDisabledPluginType)
+      handlerInfo.disablePluginType();
+
+    // Set the preferred application handler.
+    // We leave the existing preferred app in the list when we set
+    // the preferred action to something other than useHelperApp so that
+    // legacy datastores that don't have the preferred app in the list
+    // of possible apps still include the preferred app in the list of apps
+    // the user can choose to handle the type.
+    if (action == Ci.nsIHandlerInfo.useHelperApp)
+      handlerInfo.preferredApplicationHandler = aActionItem.handlerApp;
+
+    // Set the "always ask" flag.
+    if (action == Ci.nsIHandlerInfo.alwaysAsk)
       handlerInfo.alwaysAskBeforeHandling = true;
-    }
-    else if (aActionItem.hasAttribute("action")) {
-      let action = parseInt(aActionItem.getAttribute("action"));
-
-      // Set the plugin state if we're enabling or disabling a plugin.
-      if (action == kActionUsePlugin)
-        handlerInfo.enablePluginType();
-      else if (handlerInfo.pluginName && !handlerInfo.isDisabledPluginType)
-        handlerInfo.disablePluginType();
-
-      // Set the preferred application handler.
-      // We leave the existing preferred app in the list when we set
-      // the preferred action to something other than useHelperApp so that
-      // legacy datastores that don't have the preferred app in the list
-      // of possible apps still include the preferred app in the list of apps
-      // the user can choose to handle the type.
-      if (action == Ci.nsIHandlerInfo.useHelperApp)
-        handlerInfo.preferredApplicationHandler = aActionItem.handlerApp;
-
-      // Set the "always ask" flag.
+    else
       handlerInfo.alwaysAskBeforeHandling = false;
 
-      // Set the preferred action.
-      handlerInfo.preferredAction = action;
-    }
+    // Set the preferred action.
+    handlerInfo.preferredAction = action;
 
     handlerInfo.store();