Win98SE: After I set the [Accessibility] in [Control Panel] to configure the desktop to use "High Contrast Mode" with [Black on white] color scheme, the scheme button changed to [Custom] when I refer back the setting again.
To reproduce the symptom:
1) Click [Start] -> [Settings] -> [Control Panel].
2) Double-click [Accessibility Options] and select the [Display] tab.
3) Make sure that the [Use High Contrast] was checked., and then click on [Settings] button.
4) Under [High Contrast color scheme], click on [Black on white] option and click [OK] button.
5) The desktop should change the color scheme, and in the [Accessibility Options] window, click [Settings] button again.
6) In the [Settings for High Contrast] window, the color scheme changed to [Custom] instead of [Black on white].
The display color scheme of Windows has been set properly in [Black on white] scheme although the radio button now changed to [Custom]. It does not cause any problem to the computer, please use the computer as normal.