Can't change the build order on a 2D Mixed chart

I'm trying to change the build order on a 2D mixed chart, but when I open the build window and try to drag individual elements to a different order, they will not accept a new position. All I can do is drag them to join the element above.

I need to move the line graph portion of the chart to make it build last. I have noted that it is the first row in the data table and that I cannot move it from there or it changes the other values in the chart.

Any suggestions?