Simple usability/interface bug.
See issue on drupal (with images):
Perhaps a quick fix is to bold the results for the selected option rather than changing the background colour (which is already blue).
I confirm this issue on the blue backgrounded items. The searched string is not visible in it.
The other question could be, why is the first item always "marked" blue? Can we disable this somehow ?
I think the first item is always "marked blue" because it is automatically selected as the best option. Note that any selected option would have this problem of not showing the matches substring. For consistency, one could underline or bold the matching substring rather than changing the background colour.
Underlining looks already pretty well. I am considering to test a bit this fork over here:
Looks like they have fixed some issues which are still waiting over here...
Use underline to indicate search matches instead of background color.
Looks nice and resolves #727
@Cyclodex @dynamicdan Chosen now uses an underline style which closes this issue. Thanks!