Setting file type filter in the "Save As" dialog.

This sample demonstrates working with structures, PB callbacks and callback message filters.

The sample is based on SetWindowsHookEx sample from Codexchange.
http://downloads.sybase.com/codexchange/powerbuilder/454/PBNISetWindowHook.zip

The PowerScript part of the original sample was not changed.
The PBNI(C++) part was re-written in PowerScript using PBInvoke.


Before running the sample you need to migrate and full build it.
