Color Panel range is incomplete / How to pin Color Picker

[#1]

The color panel isn't displaying the complete range that it should, so the color shown in the gradient (outlined with a circle) and the one actually being applied (rectangle underneath) aren't the same.

I can tell the color gradient is similar but doesn't cover the whole range when I compare it to the Properties panel's fill Color Picker pop up.

Should these two gradients (Color Panel and Properties > Fill > Color Picker) be the same? My end goal is just to have an accurate color picker that I can always have on the screen (without having to click through to get a popup) that I can choose from. Does anyone have any advice on how to go about this, either fixing the color panel or otherwise?

[#2]

I'm sure you are aware of this but I just have to point out you still have "Solid Color" selected from the drop-down. Does this issue persist after you select "Linear Gradient"?

[#3]

The issue does persist, but the gradient I'm talking about is the place to select the color, I am trying to use a solid color.

[#4]

I just had a look. They have wrecked it in AA20 when they introduced the ugly new UI.

Here is how it looks in AA19 and all previous versions:

And here in AA20:

It's just cropped.

[#5]

How would I revert back to the 2019 version? I don't see it available in the Creative Cloud app.