Hi,

When using multicharacters keys, if a key definition entry is missing, emacs hangs and must be killed.

Example of an offending org-capture-templates definition:

(setq org-capture-templates
      '(("t" "Todo" entry (file+headline "~/somefile.org" "Tâches")
     "* TODO %?\n  %i\n"  :clock-in t :clock-resume t)
    ("l" "Mail" entry (file+datetree "~/somefile.org" "Divers")
     "* EMAIL %?\n  %i\n" :clock-in t :clock-resume t)
    ("fm" "some Menu - level 2")
    ("fmm" "template defintion - level 3 " entry (file+olp "~/somefile.org" "Level 1" "level 2")
     "* MEETING %?\n  %i\n" :clock-in t :clock-resume t)
    ("fmt" "another template definition - level 3" entry (file+olp "~/somefile.org" "Level 1" "level 2")
     "*** TODO %?\n  %i\n" :clock-in t :clock-resume t)))

The definition of the "f" key is missing.

In such case, org-mode should display a message and, do nothing or ignore
the offending tree.

Emacs  : GNU Emacs 25.1.1 (x86_64-unknown-cygwin)
 of 2016-09-17
Package: Org mode version 9.0 (9.0-dist @ /cygdrive/c/Users/re/.emacs.d/site-lisp/org-9.0/lisp/)