There are actually two modes in which the Display Manager operates. These are the "operation mode" and the "development mode".
Operation Mode
The term "operation mode" is used to describe the state of a VTS application when it is running, displaying data in real-time and enabling operators to monitor and control the equipment and systems being represented by their VTS application. When an application is in operation mode, signals can be sent to equipment, alarms can be managed, and the application appears as it would to an operator. Your application is in operation mode when the configuration toolbox is closed or when the No Tool button is selected.
Development Mode
The term "development mode" is used to describe the state of a VTS application when it is being edited or modified by a VTS developer. When an application is in development mode graphics can be modified and manipulated, and pages can be added and configured. Your application is in development mode when the configuration toolbox is open, and any tool other than the No Tool is selected.
VTS developers use both the operation and development modes in the course of developing their applications to test functionality and to enable security features. You will switch between these two modes frequently.