Problem

Read the title.

Steps to reproduce

-- minimal.lua
local ns = vim.api.nvim_create_namespace("a")
vim.ui_attach(ns, { ext_cmdline = true }, function() end)
vim.cmd("echo \"---------------- - This text is still here\"") 
vim.api.nvim_input(":set conceallevel?<cr>")

Expected behavior

:set clears old messages while ext_cmdline is active.

Neovim version (nvim -v)

NVIM v0.10.0-dev-3023+g499070148

Vim (not Nvim) behaves the same?

No external cmdline in vim. (although, maybe this is somehow reproducible in an extreme case ? )

Operating system/version

Linux ArchLinux 6.8.1-arch1-1

Terminal name/version

wezterm

$TERM environment variable

wezterm

Installation

build from source