Here is a prototype double y axis chart. Is this what you have in mind? Another option based on adamgreco's suggestion would be to have multiple metrics trended on one chart but on the same scale. Also, the hybrid would be to have 2 y axis and have multiple metrics and choose which scale they will be plotted on. These are just all ideas. What are your thoughts on this?

@hilamonster I agree with you that cross department calendar events are valuable. My suggestion was strictly cosmetic. If the calendar events are moved from the user level to the report suite level, you might change from a few per user to 50-100 calendar events per report suite, for example. I am guessing that with the current implementation and possibly any implementation, the chart would not look good with 100+ calendar events. So my suggestion was more that the user might want to hide the cal...

One thought. If you have it associated to a report suite, then charts could become cluttered with calendar events created by multiple users. For the users that don't create calendar events, there may need to be an show/hide option added.