When saving an attachment in KMail a KMessageWidget appears offering to open the location the file was saved to. This just opens Dolphin in that folder without highlighting the file. Use KIO::highlightInFileManager({urlToFile}) to have Dolphin open, scroll to, and highlight the file for convenience.
Great thanks for info I will fix kmail soon.
it's fixed in 5.8.0 I had a problem with my name in commit so it didn't change status.