Just to be clear I tried setting 'lock_system_modes" and it doesn't seem to work. switchres still seems to select it. Some of the other system resolutions work so that's why I just wanted to get rid of the one that won't display properly.
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Switchres: [ 19] 400x 300 @ 60: system mode
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SwitchRes: [sinistar] (1) vertical (240x292@60.10)->(400x300@58.64)
rng(1): 400 x 300_58.642p 19.000 [integ] scale(1, 1, 1) diff(0.08, 2.47, -1.4542) ratio(1.667, 1.027)
SwitchRes: Setting option -rotate
SwitchRes: Setting option -noror
SwitchRes: Setting option -noautoror
SwitchRes: Setting option -norol
SwitchRes: Setting option -noautorol
SwitchRes: Setting option -notriplebuffer
SwitchRes: Setting option -syncrefresh
SwitchRes: Setting option -waitvsync
SwitchRes: Setting option -nohwstretch
SwitchRes: Setting option -nofilter
SwitchRes: Setting option -cleanstretch
SwitchRes: Setting option -keepaspect
SwitchRes: Setting option -prescale 1
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Direct3D: Device created at 400x300