neoclide/coc.nvim · error

Unable to open list window.

Error message

Unable to open list window.

What it means

QuickPick.show() first opens an input window, then calls coc#dialog#create_list to create the floating list window. When that Vim function returns a falsy result the list window was not created, so coc.nvim throws this error instead of returning a QuickPick with no window.

Source

Thrown at src/model/quickpick.ts:200

    let rounded = !!preferences.rounded
    await input.show(this.title, {
      quickpick: lines,
      position: 'center',
      placeHolder: this.placeholder,
      marginTop: 10,
      border: [1, 1, 0, 1],
      list: true,
      rounded,
      minWidth,
      maxWidth: this.maxWidth,
      highlight: preferences.floatHighlight,
      borderhighlight: preferences.floatBorderHighlight
    })
    let opts: any = { lines, rounded, maxHeight, highlights, linecount: Math.max(1, lincount) }
    if (preferences.floatHighlight !== undefined) opts.highlight = preferences.floatHighlight
    if (preferences.floatBorderHighlight !== undefined) opts.borderhighlight = preferences.floatBorderHighlight
    let res = await nvim.call('coc#dialog#create_list', [input.winid, input.dimension, opts])
    if (!res) throw new Error('Unable to open list window.')
    // let height
    this.win = new Popup(nvim, res[0], res[1], lines.length)
    this.win.refreshScrollbar()
    this.bufnr = res[1]
    this.setCursor(0)
    this.attachEvents(input.bufnr)
  }

  private buildList(items: ReadonlyArray<T>, input: string, loose = false): { lines: string[], highlights: HighlightItem[] } {
    let { selectedItems, canSelectMany } = this
    let filteredItems: T[] = []
    let filtered: FilteredLine[] = []
    let emptyInput = input.length === 0
    let lowInput = input.toLowerCase()
    const scoreFn: FuzzyScorer = loose ? anyScore : fuzzyScoreGracefulAggressive
    const wordPos = canSelectMany ? 4 : 0
    for (let index = 0; index < items.length; index++) {
      const item = items[index]

View on GitHub (pinned to 50e974d969)

Solutions

1. Verify Vim 8.2+/Neovim floating window support (:echo has('float') && has('popupwin'))
2. Ensure show() is called when the editor UI is attached and the buffer is visible
3. Wrap show() in try/catch and handle the failure (fallback to a plain list via window.showPickOption style API)
4. Check for autocmnds/plugins that close floating windows immediately after creation

Example fix

// before
await quickPick.show()
// after
try {
  await quickPick.show()
} catch (e) {
  window.showErrorMessage('QuickPick window could not be opened')
}

if (!workspace.isReady) return
// Vim: :echo has('float') && has('popupwin')

try {
  await quickPick.show()
} catch (e) {
  if (e.message.includes('Unable to open list window')) {
    window.showErrorMessage('QuickPick unavailable in this environment')
  }
}

When it happens

Trigger: Calling await quickPick.show() when coc#dialog#create_list returns null/0 — floating window creation fails (no float/popup support), invalid dimension from the input window, or the input window itself was closed/invalid before list creation.

Common situations: Using QuickPick API in Vim lacking +popupwin, screen too small with maxHeight constraints, or calling show() after the quickpick was disposed/window closed by an autocmd racing the creation.

Related errors

• Unable to open input window

AI-assisted analysis of neoclide/coc.nvim@50e974d969 (2026-08-31). Data as JSON: /api/errors/dae4dc39ee7c2019. Report an issue: GitHub.