WebStorm with ideavim appears error "on-prefix)"

Question

Environment

Windows 10
WebStorm 2020.1.1

Problem

I set .ideavimrc in C:/Users/{name} like that:

・・・
let mapleader = "\<Space>"
nnoremap <Leader><Leader> :w<CR> //doesnt work
vnoremap <Leader>w :w<CR> //works!
nnoremap <leader>q :q!<cr> //works!
vnoremap <leader>q :q!<cr> //works!
・・・

Only when I touch space key two times, in the status bar of WebStorm appears like this message "on-prefix)"

Actually it worked yesterday, so I have no idea what is going on now.

Answer 1

You probably have easy-motion (VIM plugin) installed: easy-motion uses this mapping by default (i.e. this is a "mapping conflict"). I was having the same problem, tried without loading easy-motion and solved the problem.