Missing formatting bar in rich text input

[lancewl]

Hi,

I'm adding rich text input block to my modal. It does work like a rich text input since I can make a bullet point or make the bold font by using keyboard shortcut. However, the formatting tool bar seems to be missing:

I'm aiming to achieve the same appearance as the showcase from the Block Kit Builder:

Below is the code snippet for my block:

  {
      "type": "input",
      "element": {
          "type": "rich_text_input",
          "action_id": "des_key",
      },
      "label": {
          "type": "plain_text",
          "text": "Description",
          "emoji": True,
      },
  },

I would greatly appreciate any assistance on this issue. Thanks!