numeric
Whether the Control-T keyboard facility is enabled.
When sys_control_t is set to 1, pressing of the Control-T keyboad sequence makes the monitor window visible and pops it forward, equivalent to issuing the monitor command.
When it is set to 0, the Control-T keyboard sequence is ignored.
Note: On Unix systems the sequence cannot be disabled.
At system start-up sys_control_t has a value of 1.