You started a new design by clicking on the “New” button, and found Auto spacing and Underlay became greyed-out in the object properties dialog box.
This occurred because you started a new design with the Auto Fabric turned on.
You can start a new design without turning on the Auto Fabric by following the procedure outlined below:
1) Go to the File > New from Template… menu
2) In the New from Template dialog box, un-tick the check box for “Use auto fabric” (by default, it is ticked)
3) If you wish to keep the Auto Fabric off from now on when starting a new design, then click on the “Save” button to save the new setting in the template
4) Click on the “OK” button to close the New from Template dialog box.
Note: you have now started a new design without Auto Fabric. Autospacing and Underlay are now active.