In the Graph Settings window you can define the range of periods that's shown in the history chart items included in the view (indicators or other items are not affected). If you uncheck the "Use default settings" checkbox, you can define how many periods before and how many periods after the chart period are displayed in all chart items. Note that the before and after values are always applied relative to the actual middle period shown in the chart. You can click the middle period to change it. If you re-select the "Use default settings" checkbox, the charts revert to displaying the settings defined for them in QPR Metrics client.
