With \setupalign[flushleft], nonbreakable spaces get larger than they should. I'm afraid it's a bug.
Best, An MWE: \setupalign[flushleft] \starttext Lorem ipsum dolor sit~amet, consectetur adipiscing elit. Donec euismod mattis pellentesque. Duis ut ullamcorper sem. Sed varius neque quis lacus hendrerit dapibus. Ut non elit eu nibh dignissim feugiat. Quisque elementum lacinia pretium. Aliquam vel tellus in~ipsum lacinia sagittis. Morbi vitae justo ante, sit~amet vulputate sem. Vivamus faucibus ante vel dolor aliquet placerat. Ut pulvinar tellus sit~amet augue congue dapibus. Donec justo odio, dignissim id rhoncus eget, tristique at justo. Morbi quis libero id nisl malesuada aliquam non non libero. Proin tristique ultricies ipsum, vel facilisis odio luctus quis. Nullam tellus leo, posuere in~eleifend quis, lobortis eu sem. In~hac habitasse platea dictumst. Suspendisse non quam a~ante mollis dignissim. Class aptent taciti sociosqu ad litora torquent per conubia nostra, per inceptos himenaeos. \stoptext -- Marcin Borkowski http://octd.wmi.amu.edu.pl/en/Marcin_Borkowski Adam Mickiewicz University ___________________________________________________________________________________ If your question is of interest to others as well, please add an entry to the Wiki! maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context webpage : http://www.pragma-ade.nl / http://tex.aanhet.net archive : http://foundry.supelec.fr/projects/contextrev/ wiki : http://contextgarden.net ___________________________________________________________________________________