When certain kinds of events take place in graphics windows, GraphicsDesigner creates messages to describe them.

For example, when a keyboard key is pressed, GraphicsDesigner creates a WindowKeyDown message. When the mouse moves or a button is depressed, a MouseMove or MouseDown message is created. When a user clicks on a window, a WindowSelected message is created.

In general, whenever the state of the keyboard, mouse, or a window changes, GraphicsDesigner creates a message that describes it.

Only events in graphics windows are detected by GraphicsDesigner , so only events in graphics windows cause the creation of messages.

window messages and grid messages
Any particular message name, like WindowKeyDown or MouseDown , refers to either windows or grids, never both.

Window messages refer to windows.

Grid messages refer to grids.

Window message names must start with "Window".
Grid message names must not start with "Window".