to provide to its constructor two further parameters: • a model containing the current selected item. This parameter is not required if we are going to inherit a CompoundPropertyModel for this component value="1">strawberry watermelon The first option is a placeholder item corresponding to a null model value. By default DropDownChoice cannot have a null value so users DropDownChoice component can be configured to automatically update its model each time we change the selected item on the client side. All we have to do is to add a FormComponentUpdatingBehavior to it: The behavior

to provide to its constructor two further parameters: • a model containing the current selected item. This parameter is not required if we are going to inherit a CompoundPropertyModel for this component value="1">strawberry watermelon The first option is a placeholder item corresponding to a null model value. By default DropDownChoice cannot have a null value so users DropDownChoice component can be configured to automatically update its model each time we change the selected item on the client side. All we have to do is to override method wantOnSelectionChangedNotifications to

to provide to its constructor two further parameters: • a model containing the current selected item. This parameter is not required if we are going to inherit a CompoundPropertyModel for this component value="1">strawberry watermelon The first option is a placeholder item corresponding to a null model value. By default DropDownChoice cannot have a null value so users DropDownChoice component can be configured to automatically update its model each time we change the selected item on the client side. All we have to do is to add a FormComponentUpdatingBehavior to it: The behavior

to provide to its constructor two further parameters: • a model containing the current selected item. This parameter is not required if we are going to inherit a CompoundPropertyModel for this component value="1">strawberry watermelon The first option is a placeholder item corresponding to a null model value. By default DropDownChoice cannot have a null value so users DropDownChoice component can be configured to automatically update its model each time we change the selected item on the client side. All we have to do is to add a FormComponentUpdatingBehavior to it: The behavior

fles which can be referred to as header items. Header items ● As the name suggests, an header item is simply an element that is placed inside the tag of the page. In Wicket header items are HeaderItem (for example JavaScriptHeaderItem) ● A page or one of its component can add an header item overriding its method renderHead: class MyPanel extends Panel { public void renderHead(IHeaderResponse forReference(jqueryuiRef); Priority Header Item ● PriorityHeaderItem: wraps another header item and ensures that it will have the priority over the other items. The item wrapped by PriorityHeaderItem will