Hello Marco,

That's not a bug  -  it's by design.  Clicking on a field in a form gives that field focus and enables the user to position the cursor in preparation for typing, etc.

To have a tooltip pop up when the field was clicked could cause confusion, and is generally not a convention when designing web forms.

You could request that the developers consider it as an option in future versions by creating an 'Idea' post.

Kind regards,

Paul