When selecting a window, window label letter is missing when global statusline is set

[PeterDing]

Describe the bug

Neovim (https://github.com/neovim/neovim/pull/17266#issue-1120424352) is supporting to set global statusline. But, after the global statusline(:set laststatus=3) is set, when some windows are opened and selecting a file at coc-explorer window, the assisted window label letters are missing because there is ONLY one statusline.

Result from CocInfo

## versions

vim version: NVIM v0.7.0-dev+1275-g00effff56
node version: v17.7.1
coc.nvim version: 0.0.80-c01d7231 2022-03-17 01:52:16 +0800
coc.nvim directory: /Users/peter/.local/share/nvim/plugged/coc.nvim
term: tmux
platform: darwin

## Log of coc.nvim

2022-03-18T21:49:09.517 WARN (pid:87215) [attach] - Plugin not ready when received "runCommand" [ 'explorer', '--position', 'right', '--width', '30' ]
2022-03-18T21:49:09.831 INFO (pid:87215) [plugin] - coc.nvim initialized with node: v17.7.1 after 295ms
2022-03-18T21:49:10.357 INFO (pid:87215) [attach] - receive notification: runCommand [
  'coc-helper.internal.didVimEvent_m1_v0_13_0_coc_helper_1',
  'BufDelete',
  2
]
2022-03-18T21:49:10.357 INFO (pid:87215) [attach] - receive notification: runCommand [
  'coc-helper.internal.didVimEvent_m1_v0_13_0_explorer_2',
  'BufDelete',
  2
]
2022-03-18T21:49:11.495 INFO (pid:87215) [attach] - receive notification: highlight []
2022-03-18T21:49:13.374 INFO (pid:87215) [attach] - receive notification: highlight []
2022-03-18T21:49:13.803 INFO (pid:87215) [attach] - receive notification: highlight []
2022-03-18T21:49:14.690 INFO (pid:87215) [attach] - receive notification: highlight []
2022-03-18T21:49:15.677 INFO (pid:87215) [attach] - Request action: doKeymap [ 'explorer-key-n-[cr]' ]
2022-03-18T21:49:15.703 INFO (pid:87215) [attach] - receive notification: runCommand [
  'coc-helper.internal.didVimEvent_m1_v0_13_0_coc_helper_1',
  'BufWipeout',
  1
]
2022-03-18T21:49:15.704 INFO (pid:87215) [attach] - receive notification: runCommand [
  'coc-helper.internal.didVimEvent_m1_v0_13_0_explorer_2',
  'BufWipeout',
  1
]
2022-03-18T21:49:15.839 INFO (pid:87215) [attach] - receive notification: runCommand [
  'coc-helper.internal.didVimEvent_m1_v0_13_0_coc_helper_1',
  'BufDelete',
  4
]
2022-03-18T21:49:15.839 INFO (pid:87215) [attach] - receive notification: runCommand [
  'coc-helper.internal.didVimEvent_m1_v0_13_0_explorer_2',
  'BufDelete',
  4
]
2022-03-18T21:49:15.924 INFO (pid:87215) [services] - registered service "vimlsp"
2022-03-18T21:49:15.925 INFO (pid:87215) [services] - vim language server state change: stopped => starting
2022-03-18T21:49:16.128 INFO (pid:87215) [services] - vim language server state change: starting => running
2022-03-18T21:49:16.132 INFO (pid:87215) [services] - service vimlsp started
2022-03-18T21:49:16.729 INFO (pid:87215) [attach] - receive notification: highlight []
2022-03-18T21:49:18.471 INFO (pid:87215) [attach] - receive notification: highlight []
2022-03-18T21:49:19.036 INFO (pid:87215) [attach] - receive notification: highlight []
2022-03-18T21:49:20.197 INFO (pid:87215) [attach] - receive notification: highlight []
2022-03-18T21:49:23.508 INFO (pid:87215) [attach] - receive notification: highlight []
2022-03-18T21:49:25.183 INFO (pid:87215) [attach] - receive notification: highlight []
2022-03-18T21:49:25.354 INFO (pid:87215) [attach] - Request action: doKeymap [ 'explorer-key-n-[cr]' ]
2022-03-18T21:49:32.096 INFO (pid:87215) [attach] - receive notification: highlight []
2022-03-18T21:49:35.946 INFO (pid:87215) [attach] - receive notification: showInfo []

Steps to reproduce Steps to reproduce the behavior:

1. execute nvim
2. :CocExplorer ...
3. :split
4. select a file from the explorer
5. See error

Expected behavior

Additional context None