Variables
Const COMMITTING
COMMITTING: "Committing" = "Committing"
Const IDLE
IDLE: "Idle" = "Idle"
Const REDOING
REDOING: "Redoing" = "Redoing"
Const ROLLINGBACK
ROLLINGBACK: "RollingBack" = "RollingBack"
Const UNDOING
UNDOING: "Undoing" = "Undoing"
Indicates the status of the UndoManager