WebUIControl.Tooltip
From Xojo Documentation
Property (As String )
aWebUIControl.Tooltip = newStringValue
or
StringValue = aWebUIControl.Tooltip
New in 2020r1
Supported for all project types and targets.
or
StringValue = aWebUIControl.Tooltip
New in 2020r1
Supported for all project types and targets.
Text of a message displayed as a tooltip.
Notes
The tip is displayed when the user places the mouse on the control and leaves it there.
Sample Code
This code in the Shown event of a Button sets the tooltip:
Me.Tooltip = "Save changes"