However you use .NET forms, ABL supports a few mechanisms to enable .NET forms and ABL windows to work together in an ABL session. These mechanisms allow ABL windows to share the following common interactions with .NET forms:
Managing both form and window objects as a single type of form object on a session form chain
Parenting .NET forms and ABL windows to each other in combinations of form and window hierarchies using the ABL PARENT attribute
Embedding the client area of an unrealized ABL window in the client area of a .NET form, allowing the client-area widgets of the window to be displayed as part of the .NET form
Processing form and window events in common using a single set of WAIT-FOR statement and PROCESS EVENTS statement constructs
Identifying the most recent form or window to receive focus using a common ACTIVE-FORM system reference
Outside of these common form and window mechanisms, you must continue to work with individual .NET forms and ABL windows using their own instantiation and access mechanisms. Other session features, such as internationalization and localization, fonts, colors, and icon usage require coordination for which both OpenEdge and .NET provide some help. However, you might have to explicitly manage some of these features separately in both the .NET and ABL contexts in order to fully integrate .NET forms with ABL windows in your ABL application.
Managing both form and window objects as a single type of form object on a session form chain