表格未与tview一起显示

Question

Here is a simple example of tview. I am trying to put the example form in a grid.

But the form is not showing, when running the app. Any idea?

package main

import (
    "github.com/rivo/tview"
)

func main() {
    app := tview.NewApplication()
    grid := tview.NewGrid().
        SetRows(60).
        SetColumns(60).
        SetBorders(true)
    form := tview.NewForm().
        AddDropDown("Title", []string{"Mr.", "Ms.", "Mrs.", "Dr.", "Prof."}, 0, nil).
        AddInputField("First name", "", 20, nil, nil).
        AddInputField("Last name", "", 20, nil, nil).
        AddCheckbox("Age 18+", false, nil).
        AddPasswordField("Password", "", 10, '*', nil).
        AddButton("Save", nil).
        AddButton("Quit", func() {
            app.Stop()
        })
    form.SetBorder(true).SetTitle("Enter some data").SetTitleAlign(tview.AlignLeft)
    grid.AddItem(form, 1, 1, 100, 100, 100, 100, false)
    if err := app.SetRoot(grid, true).SetFocus(grid).Run(); err != nil {
        panic(err)
    }
}