Unable to remove old PreviewView icon from background to toggle btw two color palettes

[baymak]

Hello,
I wanted to duplicate the color slider with two different sets of color palette by entering the new color values under colorSliderGradient function and controlling it by using a switch to toggle. Colorslider background changes well as expected however previous slider PreviewView still appears at behind the slider in addition to new defaultPreviewView in front. Whenever toggle the slider color palette small PreviewView icons increases behind the slider. I call addColorSlider function in the view controller every time the toggle button pressed. Any idea how to remove the old PreviewView icons from background. Many thanks indeed