Smooth migration with traditional UI mode

IBM® Informix® 4GL (I4GL) and Genero Business Development Language (BDL) handle windows and form content rendering differently.

I4GL is a TUI-style product, designed to write applications for dumb terminals; Genero BDL uses real GUI rendering, with re-sizable windows and proportional fonts.

To simplify migration from TUI-style products, Genero BDL supports the traditional GUI mode.