To unify the behavior of interactive applications beyond the use of a common widget set, two different standard top-level window arrangements (widget macros called frames) have been standardized. Each of them consists of a shell widget which defines the interface to the window manager (it is decorated with a header bar by the window manager), pull-down menus at the top or command buttons at the bottom, and an arena, where widgets can be placed arbitrarily.
Chat frames are intended for long-term user interaction. They contain a menu bar at the top of the frame. The leftmost menu is always the File menu where all file-related operations are accessible. The appearance of a chat frame gives the user the impression of a virtual application, although there is not necessarily a direct correspondence between real applications (executables) and chat frames. Examples of chat frames are Figure 3.4, Figure 3.5, Figure 3.6, Figure 3.9, and Figure 4.5.
Dialog frames are intended for short inquiry-like interactions
between TCAD system and user. They contain one or more final reply
buttons at the bottom of the window. The leftmost obligatory button is
the 
button that will always pop down the dialog window.
Examples of dialog frames are Figure 3.7, Figure 3.8,
and Figure 3.10.