为什么cvxTreeSetItemCheckState函数的第4个参数，   使用1-4效果都是黑色的呢？按照说明应该分别是绿、红、灰、黑才对啊？

typedef enum evxTreeCheckState
    {
        VX_TREE_ITEM_UNCHECKED     = 0, /**<@brief  The item not checked */
        VX_TREE_ITEM_GREEN_CHECKED = 1, /**<@brief  The item checked */
        VX_TREE_ITEM_RED_CHECKED   = 2, /**<@brief  The item checked */
        VX_TREE_ITEM_GRAY_CHECKED  = 3, /**<@brief  The item checked */
        VX_TREE_ITEM_BLACK_CHECKED = 4, /**<@brief  The item checked */
    } evxTreeCheckState;