Samsung SyncMaster 550DX User Manual page 88

How display properties are shown when multiple displays are used
1
When no display is selected: The default value is displayed.
2
When one display is selected: Settings for the selected display are displayed.
3
When two displays are selected (e.g. in sequence of ID 1 andID 3): The settings for ID 1 are
displayed before the settings for ID 3.
4
When the All+Select checkbox is checked and all displays are selected: The default settings are
displayed.