When ever we add a Flip switch control on Two option field, If we add the field on any of the form then A flip-switch control's color is grey when the field is read-only, and the value in the field is "yes".
In version 9.0, when the value is "yes", the control is displayed in red regardless of whether the field is read-only or not.
A similar behavior occurs in an "toggle control" control.

It should be better if it will be possible to customize the color of certain read-only fields without changing the color completely for all the read-only fields.