Can someone put this in a more understandable way? It seems I needed to add an _Assign method in order to reference something on a form from the class, but I really don't understand why.

Access and Assign Methods

Visual FoxPro supports Access and Assign methods, which are user-defined procedures or functions that have the 
same name as a class property and have the suffix _ACCESS or _ASSIGN appended to the procedure or function 
name. You can use Access and Assign methods to execute code when querying the value of a property or 
attempting to change the property's value. Visual FoxPro executes Access and Assign methods only when querying 
or changing property values at run time, not design time. You can create Access and Assign methods separately 
and independently of each other.