Issue 1201 - Enabling/disabling ABP everywhere applies only in the next opened tab

src/plugin/PluginClass.cpp

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2015 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 467 matching lines @@
     {
       return;
     }
     if (!urlVariant || urlVariant->vt != VT_BSTR)
     {
       return;
     }
     std::wstring url(urlVariant->bstrVal, SysStringLen(urlVariant->bstrVal));
     UnescapeUrl(url);
 
-    //Register a mime filter if it's not registered yet
-    if (s_mimeFilter == nullptr)
-    {
-      s_mimeFilter = CPluginClientFactory::GetMimeFilterClientInstance();
-    }
     // If webbrowser2 is equal to top level browser (as set in SetSite), we are
     // navigating new page
     CPluginClient* client = CPluginClient::GetInstance();
     if (url.find(L"javascript") == 0)
     {
     }
     else if (GetBrowser().IsEqualObject(webBrowser))
     {
       m_tab->OnNavigate(url);
       DEBUG_GENERAL(
@@ skipping 1238 matching lines @@
           s_criticalSectionLocal.Unlock();
 
         }
       }
     }
 
     hTabWnd = ::GetWindow(hTabWnd, GW_HWNDNEXT);
   }
   return hTabWnd;
 }