From Xojo Documentation

Property (As Boolean )
aWebButton.AllowAutoDisable = newBooleanValue
BooleanValue = aWebButton.AllowAutoDisable

New in 2020r1

Supported for all project types and targets.

When True, the button is automatically disabled after it is pressed. The Pressed event handler must be implemented for the button to disable. To re-enable the button set its Enabled property to True.

Sample Code

Me.AllowAutoDisable = True