1.The RadColorPicker control receives focus when navigating with the Tab key, but it seems that the focus is not in the correct part of it. When it gets the focus is not possible to open the ColorSelector with the keyboard only. The correct behavior should be, that once it gets the focus, open/close of the ColorSelector should be achieved with Space/Enter keys.

2.Also - navigation to every color should be possible with keyboard. Selecting every color and automatic color should be possible with keyboard.

3.When using arrow keys , focus should not leave the color picker.

2 and 3 should be considered a feature request for implementing a keyboard navigation in the control.
1 is easy to achieve with setting <b>IsTabStop = False</b> on the RadColorPicker. This way the focus will be received by the underlying splitbutton. Then it will be easily opened by pressing down arrow key.

Link to the feature request => 
https://feedback.telerik.com/Project/143/Feedback/Details/216831-colorpicker-implement-keyboard-navigation-in-colorpicker-colorselector-colorpale