In general how to debug and solve key bindings overlapping? I had this problem.. Recently I add vim-latex plugin to my vim dir. After that I noticed that my ctrl-j bind is overlapped by vim-latex/plugin/imaps.vim and lost a lot of time until solved that.
By the way: there is a bug in imaps.vim i think, because there is written " map only if there is no mapping already" and my example shows opposite.
You can get fine-grained info from the :map command:
To show only mappings relevant to a particular key (in this case ctrl-J):
:map <c-j>
or, better, to show mappings for particular key as well as the script where the mapping was set:
:verbose map <c-j>
It is the addition to other people’s answers, not the answer itself.
By the way: there is a bug in imaps.vim i think, because there is written " map only if there is no mapping already" and my example shows opposite.
You are mistaking what «mapping» here means. If you take a look at the code of imaps.vim you’ll see that it won’t create a mapping if there is a mapping to <Plug>IMAP_JumpForward ({rhs}), not if there is a <C-j> mapping ({lhs}). Thus you should use
nnoremap <SID>I_won’t_ever_type_this <Plug>IMAP_JumpForward
in order to disable <C-j> remapping if you don’t need it (of course you could replace <SID>... part with something more meaningful if you do want to use this functionality).
:map
Shows a list of your current maps.
来源：https://stackoverflow.com/questions/8546495/how-to-debug-vim-mapping-overlaps