Placeholder text displays a hint to the user.
For a text input, placeholder text is shown until the user types input. If the user clears the contents of an input box, then placeholder text is re-displayed.
For a dropdown, placeholder text prompts the user to make a selection.
The placeholder is replaced after the user selects an item.
Tip: Manually typed placeholder text is ignored if the component is bound to a variable. If a variable is selected, then its value is always displayed.