diff -Naur mozilla-1.9.2/browser/base/content/browser.js mozilla-1.9.2-magellan/browser/base/content/browser.js
--- mozilla-1.9.2/browser/base/content/browser.js	2010-04-02 18:03:19.000000000 +0200
+++ mozilla-1.9.2-magellan/browser/base/content/browser.js	2010-06-07 16:42:16.000000000 +0200
@@ -5946,12 +5946,20 @@
   var pluginInfo = getPluginInfo(aEvent.target);
   missingPluginsArray[pluginInfo.mimetype] = pluginInfo;
 
+  gBrowser.selectedBrowser.addEventListener("NewPluginInstalled",
+                                            gMissingPluginInstaller.refreshBrowser,
+                                            false);
+
   if (missingPluginsArray) {
     window.openDialog("chrome://mozapps/content/plugins/pluginInstallerWizard.xul",
                       "PFSWindow", "chrome,centerscreen,resizable=yes",
                       {plugins: missingPluginsArray, browser: gBrowser.selectedBrowser});
   }
 
+  gBrowser.selectedBrowser.removeEventListener("NewPluginInstalled",
+                                               gMissingPluginInstaller.refreshBrowser,
+                                               false);
+
   aEvent.stopPropagation();
 }
 
@@ -6028,11 +6036,17 @@
   function showPluginsMissing() {
     // get the urls of missing plugins
     var missingPluginsArray = gBrowser.selectedBrowser.missingPlugins;
+  gBrowser.selectedBrowser.addEventListener("NewPluginInstalled",
+                                            gMissingPluginInstaller.refreshBrowser,
+                                            false);
     if (missingPluginsArray) {
       window.openDialog("chrome://mozapps/content/plugins/pluginInstallerWizard.xul",
                         "PFSWindow", "chrome,centerscreen,resizable=yes",
                         {plugins: missingPluginsArray, browser: gBrowser.selectedBrowser});
     }
+  gBrowser.selectedBrowser.removeEventListener("NewPluginInstalled",
+                                               gMissingPluginInstaller.refreshBrowser,
+                                               false);
   }
 
   if (aEvent.type == "PluginBlocklisted") {
@@ -6121,6 +6135,13 @@
     notificationBox.removeNotification(notification);
   }
   // reload the browser to make the new plugin show.
+
+  // reload plugins
+  var pm = Components.classes["@mozilla.org/plugin/manager;1"]
+               .getService(Components.interfaces.nsIPluginManager);
+  pm.reloadPlugins(false);
+
+  // ... and reload the browser to activate new plugins available
   browser.reload();
 }