Options that specify how elements in the panel scale when the screen size changes. See PanelSettings.scaleMode.
| ConstantPixelSize | Elements stay the same size, in pixels, regardless of screen size. |
| ConstantPhysicalSize | Elements stay the same physical size (displayed size) regardless of screen size and resolution. |
| ScaleWithScreenSize | Elements get bigger when the screen size increases, and smaller when it decreases. |