long arglist display layout problems

bug imported from https://bugs.launchpad.net/slime/+bug/627320

`(with-open-file (stream |`, then `C-c C-d A`; there's a newline after WITH-OPEN-FILE.

The reason is that the way highlighted parameters are indicated does not
play well with pretty-printing.

Luís Oliveira (luismbo) wrote on 2013-10-07:	
I can't reproduce this using SLIME from 2013-06-17 and ACL. Could it be specific to whatever Lisp you're using?