Many manufacturers have more than one EISA ID for the same model monitor. Since system-config-display is showing the entire contents of the MonitorsDB file without collating these duplicates, the UI is showing, for example, 8 listings of "Compaq 140" and "Compaq 150" system-config-display should try to filter out these duplicates somehow and only show unique monitor names in the UI.
Fixed in system-config-display-1.0.12-1 in Rawhide.