From the Edit menu, select Undo [Name of the recent action] or press Control+Z.
Each click reverses one more action. Continue clicking Undo (or pressing Control+Z) to remove as many of the previous changes as necessary.
When the Undo command is unavailable (dimmed), you cannot undo the previous action.
Adobe Captivate tracks actions from the time you open a project until the time you close the project. Therefore, you can undo as many times as you need to, as long as the project remains open.