Issue 1737 - ABP 1.3 for IE sometimes blocks navigation to the ad from Google search results

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 985 matching lines @@
     if (it != s_threadInstances.end())
     {
       tab = it->second->m_tab;
     }
   }
   s_criticalSectionLocal.Unlock();
 
   return tab;
 }
 
+bool CPluginClass::HasTabs()
+{
+  ATL::CComCritSecLock<CComAutoCriticalSection> lock(s_criticalSectionLocal);
+  return !s_threadInstances.empty();
+}
 
 STDMETHODIMP CPluginClass::QueryStatus(const GUID* pguidCmdGroup, ULONG cCmds, OLECMD prgCmds[], OLECMDTEXT* pCmdText)
 {
   if (cCmds == 0) return E_INVALIDARG;
   if (prgCmds == 0) return E_POINTER;
 
   prgCmds[0].cmdf = OLECMDF_ENABLED;
 
   return S_OK;
 }
@@ skipping 712 matching lines @@
           s_criticalSectionLocal.Unlock();
 
         }
       }
     }
 
     hTabWnd = ::GetWindow(hTabWnd, GW_HWNDNEXT);
   }
   return hTabWnd;
 }