Keeping Graph periods static

[alan_grn]

I have data which is linked to a MontYear field (Jan 2010, Feb 2010)

I have created a bar chart with time frames and would liek to do the following :

a) If a date is selcted values in tables change, but the graph is still to show all time periods.

b) If a date is slected I want to show only the last 3 periods in relation to the date selcted.