In a recent blog post Minitab blogger Eston Martz published a Pareto diagram where the first bar and the cumulative percent lines were colored red. I asked him how he did it. Here is his reply:

This is a Minitab feature you can use after the graph is created.  When you click on the bars, Minitab first selects all of the bars on your graph.  If, like me, you are a fast double-clicker, your second click will bring up a dialog box that lets you edit the color of all the bars in the graph.

The trick is to wait half a second before you click on the individual bar you want to edit. That little pause tells Minitab to reduce the selection from all of the bars to just the one you want to alter. Then you can double-click on that lone bar (or right-click on it) to call up the graph editing dialog, which will only affect the bar you selected. 

This trick might be useful in your next presentation. I think the colored first bar emphasises the fact that it's the most important problem category.