See the question and my original answer on StackOverflow

In Visual Studio Solution Explorer

  • click on any Web Form page (.aspx)
  • click on "Browse With...", that opens a dialog box
  • click the "Add" button
  • choose ""C:\Program Files\Internet Explorer\iexplore.exe" for the path (on 64-bit systems, this is IE 64) and for example "Internet Explorer 64-bit" for the friendly name
  • click on the "Set as Default" button
  • close this dialog box