Introduction to application windows

All the information that the program can give to the user is displayed in an application window. An application window can of the following types:

• graphical window,
• document window,
• preview window.

The user can use all the window types at the same time and swap between them freely, or he may use just one type at a time. It depends completely on his or her will and habits.

At the same time, as many graphical and document windows can be opened as the user considers convenient to him. On the other hand, there can be opened just one preview window.