LSP documentation on nvim-qt is narrow

FAQ

• I have checked the FAQ and it didn't resolve my problem.

Announcement

• I have checked Breaking change announcement.

Minimal reproducible full config

vim.opt.completeopt = "menu,menuone,noselect"

return require("packer").startup(function(use)
    use 'wbthomason/packer.nvim'

    use {
        "neovim/nvim-lspconfig",
        after = "cmp-nvim-lsp",
        config = function()
            local opts = {noremap = true, silent = true}
            vim.keymap.set('n', '<space>e', vim.diagnostic.open_float, opts)
            vim.keymap.set('n', '[d', vim.diagnostic.goto_prev, opts)
            vim.keymap.set('n', ']d', vim.diagnostic.goto_next, opts)
            vim.keymap.set('n', '<space>q', vim.diagnostic.setloclist, opts)

            local on_attach = function(client, bufnr)
                vim.api.nvim_buf_set_option(bufnr, 'omnifunc',
                                            'v:lua.vim.lsp.omnifunc')

                local bufopts = {noremap = true, silent = true, buffer = bufnr}
                vim.keymap.set('n', 'gD', vim.lsp.buf.declaration, bufopts)
                vim.keymap.set('n', 'gd', vim.lsp.buf.definition, bufopts)
                vim.keymap.set('n', 'K', vim.lsp.buf.hover, bufopts)
                vim.keymap.set('n', 'gi', vim.lsp.buf.implementation, bufopts)
                vim.keymap
                    .set('n', '<C-k>', vim.lsp.buf.signature_help, bufopts)
                vim.keymap.set('n', '<space>wa',
                               vim.lsp.buf.add_workspace_folder, bufopts)
                vim.keymap.set('n', '<space>wr',
                               vim.lsp.buf.remove_workspace_folder, bufopts)
                vim.keymap.set('n', '<space>wl', function()
                    print(vim.inspect(vim.lsp.buf.list_workspace_folders()))
                end, bufopts)
                vim.keymap.set('n', '<space>D', vim.lsp.buf.type_definition,
                               bufopts)
                vim.keymap.set('n', '<space>rn', vim.lsp.buf.rename, bufopts)
                vim.keymap.set('n', '<space>ca', vim.lsp.buf.code_action,
                               bufopts)
                vim.keymap.set('n', 'gr', vim.lsp.buf.references, bufopts)
                vim.keymap.set('n', '<space>f', vim.lsp.buf.formatting, bufopts)
            end

            local lsp_flags = {
                debounce_text_changes = 150
            }
            local capabilities = require('cmp_nvim_lsp').update_capabilities(
                                     vim.lsp.protocol.make_client_capabilities())
            require('lspconfig')['pyright'].setup {
                on_attach = on_attach,
                flags = lsp_flags,
                capabilities = capabilities
            }
        end
    }

    use {"L3MON4D3/LuaSnip"}

    use {
        "hrsh7th/nvim-cmp",
        config = function()
            local cmp = require("cmp")
            cmp.setup({
                snippet = {
                    expand = function(args)
                        require('luasnip').lsp_expand(args.body)
                    end
                },
                window = {
                    completion = cmp.config.window.bordered(),
                    documentation = cmp.config.window.bordered()
                },
                mapping = cmp.mapping.preset.insert({
                    ['<C-b>'] = cmp.mapping.scroll_docs(-4),
                    ['<C-f>'] = cmp.mapping.scroll_docs(4),
                    ['<C-Space>'] = cmp.mapping.complete(),
                    ['<C-e>'] = cmp.mapping.abort(),
                    ['<CR>'] = cmp.mapping.confirm({select = true})
                }),
                sources = cmp.config.sources({
                    {name = 'nvim_lsp'},
                    {name = 'luasnip'} 
                }, {{name = 'buffer'}})
            })
        end
    }

    use {"saadparwaiz1/cmp_luasnip"}
    use {"hrsh7th/cmp-nvim-lsp", after = "nvim-cmp"}
end)

Description

The LSP provided documentation popup is fine under a terminal running nvim. But the popup window in nvim-qt shows up too narrow to be useful. I am not sure if this is nvim-cmp or nvim-qt causing this.

Steps to reproduce

With pyright installed, create a new python file x.py and type in:

import os

os.path

Expected behavior

This is nvim on wezterm

Actual behavior

This is nvim-qt

Additional context

For fun, I tried it on gnvim, it looks slightly better, but not as good as the terminal one