When the multi-purpose selector of a node dialog box is set to When Changed, you can view the time and date the node was last changed, based on the clock in your computer. This value is similar to the one maintained by your computer operating system for when each file was last changed, but it can be more useful for Bayes nets since it actually records the time of change, not just the time of file saving, and it provides a separate value for each node. You cannot change this value; it is for observation only. If no value appears, it means that the time of the last change was not saved in the Bayes net file, and the node has not been changed since reading from file.