Callback on resizing

When a %pv is attached to a %gr[user_resize], then a callback is initiated on resize and the change can be handled. If a %pv is applied to a %fr or %lv or %bv, how do I get a callback to occur when they are resized.

Regards

Ian

I think that I can probably supply a way to do this but I am very short of time at the moment and it would make it easier for me if you could supply an illustrative sample program showing a control that needs to resize with the parent window.

What about %`mv ? this provides a callback when the parent is resized.