Hi,
    I'm a newbie of Atlas so, please, I apologize if I seem to be a little dummy :)
I want to make my own extender control. I started from scratch when I found the Atlas ExtenderControl. I would like to have a result similar in construction as DragOverlayExtender. I copied a little of code but my Extender doesn't works well with the designer: to extend a control I go to the designer, select the control to extend and try to go to the added property (property group) but in the property grid there's a message like this: "Property items cannot be added to, removed from, or replaced in the collection after the Init event. To dynamically add extender properties, create a new extender and add the new properties to that extender and then add the extender to the page.". I tried to extend a Panel with a DragOverlayExtender but the designer behaves in a similar way: the "value" of the added property DragOverlay is as reported below.
Solutions?
Thanks,
Gabriele