@Override
			public void paint(GGlassPane glassPane, Graphics g) {

				int alpha = 150;

				// bounds of the popup and the mouse neutral zone
				if (mouseMovementArea != null) {
					Rectangle r = mouseMovementArea;
					Point p = new Point(r.getLocation());
					SwingUtilities.convertPointFromScreen(p, glassPane);

					Color c = Palette.LAVENDER.withAlpha(alpha);
					g.setColor(c);
					g.fillRect(p.x, p.y, r.width, r.height);
				}

				// show where the user hovered
				if (location != null) {
					Point p = new Point(location);
					p = SwingUtilities.convertPoint(source, p.x, p.y, glassPane);

					g.setColor(Palette.RED.withAlpha(alpha));
					int offset = 10;
					g.fillRect(p.x - offset, p.y - offset, (offset * 2), (offset * 2));
				}
			}
Paints shapes used by this class (useful for debugging)
Ghidra/Framework/Docking/src/main/java/docking/widgets/PopupWindow.java