Missing bar in ZigZag histogram !! Help

I made a new zig zag indicator to display in price histogram (ZigZagHistBlk.mq4). Somehow when the histogram is shown, i missed some bars at the end?? When you changed to another timeframe, it appears but later gone.

Could somebody help out to see what is the reason?

Attached the files... Thanks.

p.s. ZigZagTrendIndi1.mq4 just to show the price segment.