Device information on hover
When you hover (or float) your mouse over a DM device, display information about that device in a tooltip.
For DM Electrical, possible information would include callout and circuit number
Peter Lawton commented
For Plumbing, info could include tag, description, SFUs & DFUs. For Mech: tag, description, zone, circuit. Also, there could be two 'levels of detail' for the tooltips, simple and detailed.