From Xojo Documentation
| This item was deprecated in version 2019r2.
Please use Application.ShowTooltip and Application.HideTooltip as a replacement.
Class (inherits from Object)
Used to create and display a tooltip at the user-specified location.
|This class is deprecated as mentioned above. If you still need to use this class in your 2019r2 or later projects, you must use the "Global." prefix (Example: Global.Tooltip.Hide) otherwise you will get a compilation error. However, it's recommended that you migrate to the replacement methods.|
Since the ToolTip class's methods are shared methods, you do not need to instantiate an instance of the class in order to use it.
Tooltip.Show(TextField1.Text, System.MouseX, System.MouseY + 20, True)