PRB: NULL and .NULL. Are Not Interchangeable in Properties

MORE INFORMATION

At times, you may wonder why you can enter the following in the Command window and get the expected result:

   X=NULL
   ?ISNULL(X)   <-- .T. is return
				

However, ISNULL() evaluates as .F. instead of .T. when a NULL value, without the period on both ends, is assigned to a property in the Properties window.

Steps to Reproduce Behavior

1. Create a new form.
2. Create a new property named NullProperty.
3. In the Properties window, assign NULL to NullProperty property (that is, without periods before and after NULL).
4. Put the following in the form Init:

         ?ISNULL(THIS.NullProperty)
   						

5. Run the form.

Visual FoxPro returns .F.