When changing a configuration in an overview screen, there is always the risk that users have maintained their own personalized view. The change you have made, will then not be applied to these users, unless they click the button ‘reset to default’ in the personalization screen.
You can determine which users have maintained a personal view by checking table BSPC_DL_PERSSTOR. In this table, you can select the changed view, and see the users.
You can now of course email them to delete their personalized view, or you can (a littlebit more forced) just delete the entries from the table. SAP has supplied a SE38 program to delete the personalized views.
The program is called BSP_DLC_DELETE_PERSONALIZATION.
In this program, you can set for instance the component, viewname and rolekey of the personalized views to be deleted. Be aware that the program will not show you an overview of the views to be deleted, so be sure to check the table before executing the program.