SSMS 2014 Addin ServiceCache Error

I'm trying to get the current connection using sql server 2014 (visual studio 2013), but I keep getting ServiceCache The type 'Microsoft.SqlServer.Management.UI.VSIntegration.ServiceCache' exists in both 'SqlPackageBase.dll' and 'Microsoft.SqlServer.SqlTools.VSIntegration.dll' when I put a breakpoint on the servicecache call. Anyone know of a fix for this? Any help is much appreciated!

my references are:
Microsoft.SqlServer.ConnectionInfo.dll
Microsoft.SqlServer.Management.Sdk.SqlStudio.dll
Microsoft.SqlServer.Management.SqlStudio.Explorer.dll
Microsoft.SqlServer.RegSvrEnum.dll
Microsoft.SqlServer.Smo.dll
Microsoft.SqlServer.SqlTools.VSIntegration.dll
ObjectExplorer.dll
SQLEditors.dll
SqlWorkbench.Interfaces.dll

using System.Reflection;
using System.Globalization;
using Microsoft.SqlServer.Management.UI.VSIntegration;
using Microsoft.SqlServer.Management.UI.VSIntegration.ObjectExplorer;
using Microsoft.SqlServer.Management.Common;
using Microsoft.SqlServer.Management.Smo;
using Microsoft.SqlServer.Management.Smo.RegSvrEnum;
using Microsoft.SqlServer.Management.SqlStudio.Explorer;

namespace NewAddin
{
/// <summary>The object for implementing an Add-in.</summary>
/// <seealso class='IDTExtensibility2' />
public class Connect : IDTExtensibility2, IDTCommandTarget
{
/// <summary>Implements the constructor for the Add-in object. Place your      initialization code within this method.</summary>
public Connect()
{
}

SqlConnectionInfo _myCurrentConnection = null;
private UIConnectionInfo currentUIConnection;


/// <summary>Implements the OnConnection method of the IDTExtensibility2 interface. Receives notification that the Add-in is being loaded.</summary>
/// <param term='application'>Root object of the host application.</param>
/// <param term='connectMode'>Describes how the Add-in is being loaded.</param>
/// <param term='addInInst'>Object representing this Add-in.</param>
/// <seealso class='IDTExtensibility2' />
public void OnConnection(object application, ext_ConnectMode connectMode, object addInInst, ref Array custom)
{
_applicationObject = (DTE2)application;
_addInInstance = (AddIn)addInInst;

if (Microsoft.SqlServer.Management.UI.VSIntegration.ServiceCache.ScriptFactory.CurrentlyActiveWndConnectionInfo != null)
{
//                _myCurrentConnection =     ServiceCache.ScriptFactory.CurrentlyActiveWndConnectionInfo.UIConnectionInfo;
currentUIConnection = ServiceCache.ScriptFactory.CurrentlyActiveWndConnectionInfo.UIConnectionInfo;

}

Remove reference to Microsoft.SqlServer.SqlTools.VSIntegration.dll. Then explicitly add a reference to the SQLPackageBase.dll

From the same location

C:\Program Files (x86)\Microsoft SQL Server\110\Tools\Binn\ManagementStudio\

That fixed it for me locally.