If provided hintText in InputDecoration then it's not invisible when typing and searching in Mode.MENU.

[Naimehossein77]

If you give hintText then open the dropdown and type to search in list items then it's not hiding the hintText.
I tried it on WEB.

[Adeel-Sultan]

@HASHCAPDOTCOM please solve this issue, we are facing on Web
let me attach screenshot

[Kapish26]

Give it a labelText and set floatingLabelBehavior: FloatingLabelBehavior.never,
This will solve your issue