placeholder next/prev mapping `<Tab>` interfere with completion pum

[ikcalB]

I really would like better integration with deoplete, as this completion source was designed for that plugin.
It is very convenient to use only when completing things, however I cannot find a solution to this problem:

When having the following configuration

        let g:clang2_placeholder_next='<Tab>'
	inoremap <expr> <Tab> pumvisible() ? "\<C-n>" : "\<Tab>"

deoplete-clang2's placeholder_next always takes precedence.

TL;DR

It is not possible to continue to the next completion item with <Tab>, because clang2's placeholder jumping algorithm takes over an the currently active item is used.

[ratheesh]

Even I have this problem. It will be nice to have a fix for this issue.