Cicode tasks (or threads) can be executing in either foreground or background mode. A foreground task is one that displays and controls animations on your graphics pages. Any expression (not a command) entered in a property field (that is Text, Rectangle, Button, etc.) is executed as a foreground task. Any other commands and expressions are executed in background mode.
The difference between a background and foreground task is that a background task can be pre-empted. That is, if system resources are limited, the task (for example, the printing of a report) can pause to allow a higher priority task to be executed. When the task is completed (or when system resources become available) the original task resumes. Foreground tasks are the highest priority and can not be pre-empted.
Performing Advanced Tasks