The RefreshProperties attribute tells property editors such as the Properties window how to refresh other properties when the value of this one changes. You can set this value to None, Refresh, or All.
This example provides a read-only property named TimeNow. The Properties window displays it as a grayed-out, non-editable property that shows the current time including seconds.
The RefreshesAll property has RefreshProperties set to All. When you modify this property's value, the Properties window reloads all other property values and you can see the value of TimeNow change.