From Xojo Documentation

Property (As Boolean )
aBevelButton.Value = newBooleanValue
BooleanValue = aBevelButton.Value

Supported for all project types and targets.

If True, the button appears depressed.

Sample Code

This code is in the Action event of a CheckBox. It toggles the state of the BevelButton depending on whether the CheckBox was checked.

If Me.Value Then
BevelButton1.Value = True
BevelButton1.Value = False
End If