With the option OFF, when Perform Actions is used Design Manager shows the structure in its new form in the Current Filename column.
With the option ON, when Perform Actions is used Design Manager continues to show the structure in it's old (past tense) form in the Current Filename column. This prohibits you from performing any new actions as you are working from a no longer accurate structure. This option is OFF by default so it requires the user to turn it on if they wish to use it that way.
Ken Production: SE 2019 MP5, Testing: SE 2020 http://Grundey.blogspot.com