fix(extui): reposition "more" window after entering cmdwin

Problem:  Closing the "more" window for an entered cmdwin in ff95d7ff9
          still requires special casing to properly handle "more" visibility.
Solution: Reposition the "more" window instead; anchoring it to the
          cmdwin.

runtime/lua/vim/_extui/messages.lua

@@ -433,13 +433,14 @@ function M.set_pos(type)
   local function win_set_pos(win)
     local texth = type and api.nvim_win_text_height(win, {}) or 0
     local height = type and math.min(texth.all, math.ceil(o.lines * 0.5))
-    api.nvim_win_set_config(win, {
+    local config = {
       hide = false,
       relative = 'laststatus',
       height = height,
       row = win == ext.wins[ext.tab].box and 0 or 1,
       col = 10000,
-    })
+    }
+    api.nvim_win_set_config(win, config)
     if type == 'box' then
       -- Ensure last line is visible and first line is at top of window.
       local row = (texth.all > height and texth.end_row or 0) + 1
@@ -454,12 +455,18 @@ function M.set_pos(type)
       -- It's actually closed one event iteration later so schedule in case it was open.
       vim.schedule(function()
         api.nvim_set_current_win(win)
-        api.nvim_create_autocmd('WinLeave', {
+        api.nvim_create_autocmd({ 'WinEnter', 'CmdwinEnter', 'CmdwinLeave' }, {
-          once = true,
+          callback = function(ev)
-          callback = function()
+            if ev.event == 'CmdwinEnter' then
+              api.nvim_win_set_config(win, { relative = 'win', win = 0, row = 0, col = 0 })
+            elseif ev.event == 'CmdwinLeave' then
+              api.nvim_win_set_config(win, config)
+            else
               if api.nvim_win_is_valid(win) then
                 api.nvim_win_set_config(win, { hide = true })
               end
+              return true
+            end
           end,
           desc = 'Hide inactive "more" window.',
         })

runtime/lua/vim/_extui/shared.lua

@@ -65,7 +65,7 @@ function M.tab_check_wins()
         anchor = type ~= 'cmd' and 'SE' or nil,
         hide = type ~= 'cmd' or M.cmdheight == 0 or nil,
         title = type == 'more' and 'Messages' or nil,
-        border = type == 'box' and not o.termguicolors and 'single' or border or 'none',
+        border = type == 'box' and 'single' or border or 'none',
         -- kZIndexMessages < zindex < kZIndexCmdlinePopupMenu (grid_defs.h), 'more' below others.
         zindex = 200 - (type == 'more' and 1 or 0),
         _cmdline_offset = type == 'cmd' and 0 or nil,
@@ -88,7 +88,7 @@ function M.tab_check_wins()
         api.nvim_set_option_value('smoothscroll', true, { scope = 'local' })
         local ft = type == 'cmd' and 'cmdline' or ('msg' .. type)
         api.nvim_set_option_value('filetype', ft, { scope = 'local' })
-        local ignore = 'all' .. (type == 'more' and ',-WinLeave,-TextYankPost' or '')
+        local ignore = 'all' .. (type == 'more' and ',-TextYankPost' or '')
         api.nvim_set_option_value('eventignorewin', ignore, { scope = 'local' })
       end)
     end