@sticilface There is no automatic fallback to the W channel. This was by design. The W can be warm, natural, or cold (at least I have seen only three so far). With R,G, and B set at the same value, the white it produces is different than the W channel. So, I left it up to the consumer to apply what they want.
NOTE: RgbwColor initialized with a single value like
RgbwColor(128) will set the W channel only.
NOTE: RgbwColor initialized with a HtmlColor will use the upper byte (often referred to as the A or X) as the W channel. But the RgbColor will ignore it.