The auto-detection of high contrast mode is very naive when considered in the context of fairly typical Linux desktop environments.
Many Linux systems ship with a dark theme by default with which it is very easy to trigger the high contrast mode, and rather awkward to disable (see bug #67859).
I've pushed a patch to master:
Which disables this auto-detection by default; a user can still turn that on again if they want. I'd love to back-port this to 4.1.x - but it'd be good to have some UX input on this.
The previous algorithm looks for a couple of theme colours and if both are dark auto-switches to 'high contrast mode'. IMHO our high contrast mode should be implemented by using a different set of theme colours rather than this approach but ...
Other ways to detect under Linux might be to grok the theme name and if it includes 'highcontrast' then enable that setting, otherwise never do it.
Thoughts from designers / UX advice much appreciated.
please give an update of the current bug status after Micheal's patch.
if bug is not present anymore please set status to FIXED
Indeed, this one is pushed in the current master, closing.