Marker size or shape in legend for combo chart

I currently have a combo chart (stacked column with a line showing the average). When I create a regular stacked column chart, the legend entry markers are squares. However, when I add the line as a combo chart, the markers become rectangles. It seems like this goes back quite a few versions of Excel from pictures I've seen on Peltier's blog.

Does anyone know if this can be changed? It looks odd in the presentation I have because the "Average" line looks almost as thick as the rectangles representing the series.

Thanks in advance!!

-njs


(Using Excel 2013)

Originally Posted by Andy Pope

The marker will elongate as soon as you mix chart types with a line.

You can either remove it from the legend and label the line itself or resort to a shape for the legend entry

Is there a reason they change it for these chart types?