I'm not sure what you mean by RGB color wheels?
As color wheel and RGB color mixing are two different color options.
For the Color wheel you have a group of color buttons.
For RGB color mixing you have a color pick pallet for color picking. where you can click on the exact color you want.
If this is what your refering to then you must be pressing the button rearangement icons at the top of the page.
You must be in compression mode for the color pick pallet to show.
Here is a small image.
