Currently, with the Windows 11 theme, the animation is applied via DoubleAnimationUsingKeyFrames, which sets the Width and Height properties of the element that represents the thumb of the RadToggleSwitchButton to 14px, which does not take into account the ThumbWidth/ThumbHeight properties.

We can improve the animation applied to the thumb for the mouse-over state to take into account the values of the ThumbWidth/ThumbHeight and properties.