In versions 8.0 and earlier of the BMC Remedy AR System Developer Studio, the form properties were accessed with the Form->Form Properties menu to open a dialog box.  This has changed in AR System 8.1.  I spent a lot a time wondering what I did wrong (and switching between base and overlay modes).  But I finally found it.  The form properties are now shown in the Definitions tab beside the view tab(s):



You should be in Base Development Mode to modify the form properties.