Looks like that bug never got logged. I just logged it as https://mcneel.myjetbrains.com/youtrack/issue/RH-43457
This bug will be fixed in the first service release. An SR1 release candidate will go out almost immediately after 6.0 is released.
There are 7,549 open issues on our bug tracker logged toward Rhino for Windows. Almost none of them will be fixed before we ship Rhino 6.