Chrome, pdf display, Duplicate headers received from the server

I have a section on a website where I display a pdf inside a light box. The recent chrome upgrade has broken this displaying:

Error 349 (net::ERR_RESPONSE_HEADERS_MULTIPLE_CONTENT_DISPOSITION): Multiple Content-Disposition headers received. This is disallowed to protect against HTTP response-splitting attacks.

This still works correctly in IE.

I'm using ASP.NET MVC3 on IIS6

The code I use to generate the file is as follows.

If I remove the inline statement then the file downloads, however that breaks the lightbox functionality.

Problem Code

public FileResult PrintServices()
{
    //... unrelated code removed
    MemoryStream memoryStream = new MemoryStream();
    pdfRenderer.PdfDocument.Save(memoryStream);
    string filename = "ServicesSummary.pdf";

    Response.AppendHeader("Content-Disposition", "inline;");

    return File(memoryStream.ToArray(), "application/pdf", filename);
}

The Fix

Remove

Response.AppendHeader("Content-Disposition", "inline;");

Then Change

return File(memoryStream.ToArray(), "application/pdf", filename);

to

return File(memoryStream.ToArray(), "application/pdf");