# Events Overview

Certain user operations on the GUI, such as selecting a menu item on the GUI or typing a value in a control, are called events. The User Interface Library provides the link between events and the code files in your project.

By implementing event callback functions, your program can recognize events and execute the code in response to them. The following table shows all of the events that are generated from the GUI.

## Events

EVENT_ACTIVE_TAB_CHANGE | EVENT_IDLE
EVENT_ACTIVE_CELL_CHANGE | EVENT_KEYPRESS
EVENT_CLOSE | EVENT_LEFT_CLICK
EVENT_COLLAPSE | EVENT_LEFT_DOUBLE_CLICK
EVENT_COLUMN_SIZE_CHANGE | EVENT_LOST_FOCUS
EVENT_COMBO_BOX_INSERT | EVENT_MARK_STATE_CHANGE
EVENT_COMMIT | EVENT_PANEL_MOVE
EVENT_DISCARD | EVENT_PANEL_SIZE
EVENT_DRAG | EVENT_RIGHT_CLICK
EVENT_DROP | EVENT_RIGHT_DOUBLE_CLICK
EVENT_DROPPED | EVENT_ROW_SIZE_CHANGE
EVENT_EDIT_MODE_STATE_CHANGE | EVENT_SELECTION_CHANGE
EVENT_END_TASK | EVENT_SORT
EVENT_EXPAND | EVENT_TIMER_TICK
EVENT_GOT_FOCUS | EVENT_VAL_CHANGED
EVENT_HSCROLL | EVENT_VSCROLL

Callback Schemes

Callback Precedence

Receiving Events

Swallowing Events

Processing Events

Posting Events

Queueing Events

Simulating Events