Author: Andrew Davis
MDL-45282 core_user: fixed up some oddities in the bulk user messaging screen
http://git.moodle.org/gw?p=moodle.git;a=commit;h=21a1cee1060b4e6db6ae506d59fe134ed05226f9
http://github.com/moodle/moodle/commit/21a1cee1060b4e6db6ae506d59fe134ed05226f9
+ 2.6 en [sitemessage,core]