Zend certified PHP/Magento developer

Line in Combo Chart in Pivot Chart

I am using a pivot chart that has a combo graph. On there I have 5 sets of data, and using bars for 3 of those data sets and line for 2 of those sets. When I select only 1 of the 4 months on my chart, the lines disappear. Is there any way to make lines appear when viewing only one month of data on the graph/chart?