Restores (shows) a widget element on the stage.
The restoreElement() function returns a Promise that is resolved when the element is restored. You can only restore elements that are part of the widget with which the panel is associated.
The element selector is a string with the hash symbol (#) followed by the ID of the item you want to select (for example, "#myElement").  To use this function on an inner (nested) widget, use getScopedWixEditor().
An element selector.