I have bundles ultisnips and youcompleteme installed on my macvim.
The problem is that ultisnips doesn\'t work because tab is bound by ycm.
I tried putting let g:UltiS
Based on Siegfried's answer, I am using the following which seems more natural:
let g:ycm_key_list_select_completion = ['']
let g:ycm_key_list_previous_completion = ['']
let g:UltiSnipsExpandTrigger = ""
let g:UltiSnipsJumpForwardTrigger = ""
let g:UltiSnipsJumpBackwardTrigger = ""
I also use the c-hjkl bindings somewhere else (switching from a pane to another), but that would only be in normal mode, so there's no problem.