Content-Disposition-Filename only works fine in Firefox

Hi guys, 
I am using a Handler.ashx for displaying a pdf in a popup, when the file is going to be downloaded I assign the filename by setting the Content-Disposition: 
context.Response.AddHeader("Content-Disposition", "inline; filename=test.pdf"); This only works in Firefox, not in IExplore or Chrome, can I do something or is due to the pdf plugin?
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