Completion menu is covered by other lower priority popup

[obcat]

Describe the bug

The zindex of insert mode completion menu is 100, but it is covered by other popup with lower zindex value, such as 10.

To Reproduce

1. Run vim -N -u minimal_vimrc.

   " minimal_vimrc
   call plug#begin()
   Plug 'prabirshrestha/asyncomplete.vim'
   Plug 'prabirshrestha/vim-lsp'
   call plug#end()

2. Create a popup with zindex of 10.

   :call popup_create(['xxx', 'xxx'], {'zindex': 10})

3. Show completion menu around the popup.

4. Completion menu is covered by the popup.

Screenshots

(Highlighted popup for clarity)

Expected behavior

Completion menu is not covered by lower priority popup.

Environment

• Vim 8.2.2300
• macOS Catalina (version 10.15.7)
• iTerm2

Additional context

The fact that the zindex of completion menu is 100 is mentioned before :h popup-props.

Depending on the "zindex" the popup goes under or above other popups.  The
completion menu (|popup-menu|) has zindex 100.

[prabirshrestha]

completion menu is using default vim completion menu. so nothing we can do here. if you are manually creating a popup you can get the position and width/height of the complete menu and position it correctly.

not a bug in vim-lsp

[obcat]

I supposed this was a bug in either vim-lsp or asyncomplete.vim, since I couldn't reproduce it without them.
I wonder if this is caused by unknown bug in Vim.

Anyway, I understood that this cannot be fixed. Thank you.