../gs_form_widget_fields_multi_image_picker_field/GSMultiImagePickerField/key.html">key</a> allows the element
to be moved around the tree (changing parent) without losing state. When a
new widget is found (its key and type do not match a previous widget in
the same location), but there was a widget with that same global key
elsewhere in the tree in the previous frame, then that widget's element is
moved to the new location.</p>
<p>Generally, a widget that is the only child of another widget does not need
a