When specifying a clear color in the PanelSettings, the color is applied as-is. For example, we can specify (1,1,1,0.5) and this value will be used as-is to clear the render texture (assuming that the proper clear flag is set). This is incorrect because the content of the render texture is premultiplied. As a result, any blend with this background color will yield an incorrect result. The user should still specify the color as straight, but UIToolkit must premultiply by the alpha internally before clearing.