When the subject was changed (prefilters added, columns added, column order changed etc.). The way the screen was intended to be used can be changed as well. In this case the user preferences should be rebooted to default settings. The user is not always aware of a screen changing.
To make this more user friendly it would be great if when a new project version is activated a popup will be shown on changed subjects after first opening the subject. The popup would give a message indication the subject was changed and it is advised to reset the screen to the default settings. This has 2 advantages: it gives the user a notification the screen was changed, and it gives the user the option to reset after a change to the screen.