In VLF-WIN

In VLF-WIN the system IIP (Imbedded Interface Point) provide four methods that you can overload to perform special logic whenever the main window or a secondary window is opened or closed.

These are called:

Refer to Imbedded Interface Points (IIPs) and the shipped version of reusable part UF_SYSTM for more information about these methods and about how to implement you own IIPs.