How to insert first item when press <Tab> in cmdline mode?

[zoumi]

With the default map of <Tab>, if I press <Tab> first time when the menu popup, it selects and inserts next item.
I want to insert the first item instead.

[eikenb]

I have this in my blink keyboard options and my tab behaves as you'd like.

    keymap = { preset = 'none', -- no preset/default keymap
      ['<Down>'] = { 'select_next', 'fallback' },
      ['<Up>'] = { 'select_prev', 'fallback'},
      ['<Tab>'] = { 'accept', 'fallback' },
    },

[Saghen]

cmdline = {
  keymap = {
    ['<Tab>'] = { 'show_and_insert', 'select_next' }
    -- or to match neovim cmdline behavior better
    ['<Tab>'] = { 'show_and_insert_or_accept_single', 'select_next' }
  }
}

By default, the cmdline.keymap.preset = 'cmdline' includes this keymap, and that preset is used by default.