| User interface / Form specification files | |
In the graphical mode (GUI mode), forms are not displayed in a fixed text-mode screen. Application windows can display complex layouts and are re-sizable by the end user.
However, forms are designed in text mode by the application developer, as .per form specification files. In order to display text-based forms in graphical mode, the front-end rendering system has to manage a character-based definition, which implies specific layout rules, explained in this section.