Binding component visibility attribute to another form value

[Sam Barnum]

I'm writing a form (non-ajax) in which a selection from a  
DropDownChoice makes various other items on the form visible or  
invisible.

I'd like to bind this behavior up lazily using properties, instead of  
making field variables for all the visible/invisible components.

It seems like writing a custom behavior is the right way to do this,  
but once I call setVisible(false) on a component the beforeRender()  
method in my behavior doesn't get called anymore, and the component  
never becomes visible.

Here's a sketch of the code:

Form form = new Form("form");
add(form);
DropDownChoice report = new DropDownChoice("report" ; new  
PropertyModel(this, "selectedReport"), reportOptions );

WebMarkdupContainer f1 = new WebMarkupContainer("f1");
f1.add(new AbstractBehavior() {
        public void onComponentTag(Component component, ComponentTag tag) {
                // only show the component if it's enabled for the selected 
report
		component.setVisible(selectedReport != null &&  
selectedReport.isField1Enabled());
                super.onComponentTag(component, tag);
        }
} );
form.add(f1);
f1.add(new TextField("myTextField"));

It seems like the isTemporary() method in my behavior gets called,  
even if the component is invisible. This hardly seems like the right  
place to put the code, though.

Should I always keep the component visible and have my behavior  
replace all the contents after rendering?

-Sam Barnum