restricting X axis date range

Being a new year, I am updating my financial tracking spreadsheet. Every year, I add a bit more, mainly for S&G. This year, I want to add a 50 day trailing average line to the stock market. So, in a stroke of genius, I plopped those values into the spreadsheet. The graph shows a plot of the average. Woohoo. But, now I want to hide those fifty days before the first of the year. How do I do that. I know I can delete those cells that show the date for those days, but I want to have the graph start at the Y-Axis, not out in space. I realize that this is a category graph, so that is not intuitively obvious.

But as an enhancement request, would a slider to restrict the beginning of the plot range be cool? Also, a slider to restrict the end of the range.

I can click on Hidden Data, but that kind of munges the 50 day average graph.

any other suggestions?