Newdigital,
Thank you very much for your kind explanation. Now I am clear. But I still need some one to help me modify it when the arrow comes it alarm immediately.

I have another problem.

I recently written an EA myself according to BT2signal indicator signal and try to do back test on Daily time frame and found that the main window Time bar has time error. The time between Time[0] - Time[1] or Time[1] - Time[2] or Time[2] - Time[3] is not all equal to 1440 minutes. And it is not consistance either. Sometimes it show 1440 or 2880 or 4320. But there is no problem on time frame H4 and below. And I confirmed that it is MetaTrader error.
So my back test result is not correct in this case. I do not know any one of you has the same problem and how to solve it?

If you do write EA yourself, put the following to your EA and you will see what I meant. When is running press F3 and refresh F3 every new time frame comes and you will see the result.

GlobalVariableSet("Time[3]-Time[2]"+Symbol(), (Time[2]-Time[3])/60);
GlobalVariableSet("Time[2]-Time[1]"+Symbol(), (Time[1]-Time[2])/60);
GlobalVariableSet("Time[1]-Time[0]"+Symbol(), (Time[0]-Time[1])/60);

Can any one help?

Thank you.

Tin