The debug overlay highlights docking-related controls in the visual tree.
When enabled each DockControl gets an adorner that draws:
Hovering over an area fills it with a translucent color and shows the hovered control’s data context in the bottom-right corner.
Attach the overlay in your application just like Avalonia’s dev tools. It can be toggled at runtime using F9 by default:
#if DEBUG
var disposable = this.AttachDockDebugOverlay();
#endif
Call the extension method on your App or on a specific Window/TopLevel to
register the hot key. Optionally pass your own KeyGesture to change the
shortcut.