Currently, the banners:textContent setting has type markdown but the large code editor creates false impression that users can add a lot of text into that space, while only one line of text is displayed. If the provided banner text is too long, it overflows from the banner:

The following short-term solutions were discussed so far:

• Adding maxLength to the schema object in the setting definition so that a validation message is displayed if the input is longer than that (the validations are currently implemented in serverless only so this will work once we integrate the new Advanced settings packages into self-managed).
• Change the input element to make it clearer visually that we're expecting shorter, single line content (rather than the larger Monaco editor, which implies opportunity for much longer content). The text input should still indicate and accept Markdown syntax.

Related customer support issue: https://github.com/elastic/enhancements/issues/20221