Default slice opacity [0 - 100]. You can set individual alphas for every slice in data file. If you set alpha to 0 the slice will be inactive for mouse events and data labels will be hidden. This allows you to make not full pies and donuts.

public byte SliceAlpha { get; set; }

Public Property SliceAlpha As Byte

public:
property unsigned char SliceAlpha {
	unsigned char get ();
	void set (unsigned char value);
}