A rectangular box for designing UIs. A rectangular box that displays only a colored border around its rectangle (see [method Control.get_rect]). It can be used to visualize the extents of a [Control] node, for testing purposes. Sets the border color of the [ReferenceRect]. Sets the border width of the [ReferenceRect]. The border grows both inwards and outwards with respect to the rectangle box. If [code]true[/code], the [ReferenceRect] will only be visible while in editor. Otherwise, [ReferenceRect] will be visible in the running project.