Problem:
OFN-ALLOWMULTISELECT flag can be set from the WinAPI GetOpenFileName function to specify that the File Name list box allows multiple selections in the open file dialog box. This however causes dialog box to use the old-style user interface.
Resolution:
It is documented from the Microsoft MSDN site (http://msdn.microsoft.com) that you need to set also the OFN-EXPLORER flag to have the dialog box to use the Explorer-style user interface. If this flag is not set, then it will use the old-style user interface.
Old KB# 1246
