Cannot see <Space> mappings

[jandamm]

Instructions: Replace the template text and remove irrelevant text (including this line)
Warning: if you don't fill this issue template and provide the reproducible steps the issue could be closed directly.

Environment (please complete the following information):

• OS: macOS 10.15.6

• (Neo)Vim version: nvim 0.4.3

• vim-which-key version: 4e5bd49

• Have you reproduced with a minimal vimrc: yes

Describe the bug
I cannot see a <Leader><Space> or <Leader><Leader> mapping.
I cannot use a <Leader><Tab> mapping.
All works just fine outside of vim-which-key but not when the window is opened.

To Reproduce
Steps to reproduce the behavior:

1. Create the minimal vimrc min.vim:

set nocompatible
set runtimepath^=/path/to/vim-which-key
syntax on
filetype plugin indent on

let g:mapleader = "\<Space>"
nnoremap <silent> <leader>      :<c-u>WhichKey '<Space>'<CR>

nmap <Leader><Tab>    :bn<CR>
nmap <Leader><SPACE>  :bp<CR>
"nmap <Leader><Leader> :buffers<CR>

2. Start (neo)vim with command: vim -u NONE min.vim -c 'so %'

3. Type and wait for a second.
   Then try or again

4. See error
   doesn't show up. shows up but isn't usable.

Expected behavior
I would expect both mappings to appear and work.

Screenshots

[jandamm]

Got it working:

TAB

Seems to only work when a keymap is registered:

call which_key#register('<Space>', 'g:which_key_map')
let g:which_key_map =  {}

and it works.

Space

Must be set as a nmap and as registered

call which_key#register('<Space>', 'g:which_key_map')
nmap <silent> <Leader><SPACE> :bp<CR>
let g:which_key_map =  { ' ': ['bp', 'title' ]}

and it works.

[jandamm]

I would still consider (at least) the mapping as an issue.

[sooriravindra]

Hit this issue today and the workaround was very helpful. Thank you @jandamm