The "Show Historic Prediction" checkbox is not shown on the mining model views of a time series prediction

1. Got to the Mining Models tab for the Time Series Prediction model in the design mode.
2. Right click ->Set Algorithm Parameter
3. Set the Historical_Model_GAP to a number (e.g., 6 for 6 time slices between historical models on p.418 of the 70-448 Self-paced Training Kit book)

But if you set it to 1 or >7, the Show Historic Predictions checkbox will not be shown, that's why initially the option was not available as the default value is 10.