Invalid window id error

[jaekyeom]

Describe the bug
I believe this is different from #151 .

EDIT: It seems that the error could be a conflict with one of the other plugins.
But I wonder if there is something like attach_mode = "buffer".

System information

• OS: linux, mac
• Neovim version: NVIM v0.7.2
• AerialInfo:

Aerial Info
-----------
Filetype: python
Configured backends:
  lsp (supported) (attached)
  markdown (not supported) [Filetype is not markdown]
Show symbols: Class, Constructor, Enum, Function, Interface, Module, Method, Struct

• Aerial config:

    aerial.setup({
        backends = {
            ['_'] = { "lsp", "markdown" },
            ['markdown'] = { "markdown", "lsp" },
        },

        layout = {
            default_direction = "prefer_left",
        },

        default_bindings = true,

        filter_kind = {
            ['markdown'] = {'String'},
        },
    })

To Reproduce
Steps to reproduce the behavior:

1. Open Aerial
2. :vsplit
3. :quit the older window

Screenshots

Screen.Recording.2022-09-20.at.12.07.04.AM.mov

Additional context

[stevearc]

I couldn't repro (as you mentioned, it is likely an interaction with another plugin), but I added some nvim_win_is_valid guards that should prevent the error

[jaekyeom]

Thanks for the patch, I appreciate your work!