When a user interacts with a Desktop icon or window background, the interaction is looked up in the trigger table to derive the trigger name corresponding to that action.
For example, if a user double-clicks on an icon with mouse button 1, this is converted to the trigger name activate in the trigger table. The Desktop then executes the command:
actions_of activateArguments are set to the appropriate values for the triggered icon and the icon's location.
The actions_of command searches the icon_rules clauses that match the triggered icon for the following clauses:
The above clauses specify an exact match, a match against any static trigger, and a match against any trigger at all, respectively.
The first match found causes a new thread to be created to execute the script specified in the trigger_action clause.