fundamental concepts

Your programs can create and operate any number of graphics windows, each of which is a rectangular area on the display screen.

Each window can contain any number of GUI components: buttons, labels, text-areas, dialog-boxes, etc.

window type
Windows have several optional features, including minimize and maximize buttons, system menu button, title-bar, and resize frame. Any combination of these defines the window type of a window.

window function
The function responsible for operating a particular window is called its window function. In most programs, every window is controlled by XuiWindow() , the GuiDesigner standard window function, so you may never think about window functions again.

A GUI components is called a grid, a term from GraphicsDesigner.

To GraphicsDesigner programs, a grid is a rectangular area in a window with its own coordinate system and graphics properties like backgroundColor, drawingColor, etc.

To GuiDesigner programs, a grid is a familiar GUI component like a label, pushbutton, text-line, dialog-box, etc.  At heart, all grids are graphics grids.  But you'll probably never think of them that way because GuiDesigner adds properties and a "grid function" to make them look and act like the GUI components in your GUI programs.

Each GuiDesigner grid is:
  A basic graphics grid from GraphicsDesigner, plus
  properties that make it look and behave like a GUI component, plus
  a "grid function" that creates, operates, and responds to events in the grid

Some kinds of grids contain other grids. Dialog boxes, for example, contain a Label grid, a TextLine grid, and one or more PushButton grids.  The grids inside other grids are called kid grids, or just kids, and are identified by kid numbers.  The Dialog box is their parent.

Kid numbers begin with 0 for the grid itself, followed by 1,2,3... for its kids, numbered from left to right from top to bottom.