Is your feature request related to a problem? Please describe.
I see several people asking in the Details Discord for a Display to show healing and overhealing similar like Skada does that.

Describe the solution you'd like
Based on that I'm proposing a feature for custom displays: Overlays

They would create more possibilities to show some more specified info without having multiple different windows open. Some examples would be:

• Total Healing + Overhealing Overlay
• Total Dispells + Dispells of specific spells Overlay
• Total Damage done + Damage done to specific NPC Overlay
• Total Interrupts + Interrupts against specific NPC Overlay

I'm not that familiar how exactly Displays work in Details, but im thinking of changing the color of a percentage of a
bar based on the maximum. So if a player does 20 Dispells and 5 of them are a specfied buff, 1/4 of the bar would change color (clamped to the start or the end of the bar).

This would open alot of customizability for displays to create your own personal set of windows to gather information visually without having to hover over and reading the tooltip.

Describe alternatives you've considered
Just thinking more general an overlay could be also enabled for already integrated Displays by using the information from data3.