TextField.Hint
From Xojo Documentation
Property (As String )
aTextField.Hint = newStringValue
or
StringValue = aTextField.Hint
New in 2019r2
Supported for all project types and targets.
or
StringValue = aTextField.Hint
New in 2019r2
Supported for all project types and targets.
Use to display a hint in the field. The Hint appears in the TextField in grey text.
Notes
On Windows and Linux, the Hint only appears when the TextField does not have focus.
Example
This example is in the Open event of the control:
Me.Hint = "Enter something"