In the staff client, there is a "place hold" button in the "cat-toolbar". This button is displaying in every view except the MARC view. Best guess at an explanation : To display this button we check for the presence of items that are available for loan. This check used to be done on the appropriate 995 subfield in this view. Which doesn't work anymore since we don't manage items in the marcxml any longer. Tested on a recently imported biblio on my local install, the place hold button doesn't display, but on a biblio that was imported when items where still managed in the marcxml (which has 995 in the marcxml) the button displays properly.
See also : Bug 8481 - Items table is showing in opac-MARCdetail.pl but not in MARCdetail.pl http://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=8481
see bug 8481 patch
*** This bug has been marked as a duplicate of bug 8481 ***