Thank you Jeff.
Sorry I am very foolish. I don't understand what you are talking about at all.
For me, if I open an intraday chart (1m, 10m, 1h, 10h, tick, renge, volume, ... whatever) of a symbol that I never opened an intraday chart before, I can only get total 5 day's data. No matter how many times I hit 'backfiil chart for...' still only 5 day's data.