String generateToolTip(MouseEvent event) {
		if (pixmap == null) {
			return null;
		}

		int y = event.getY();
		int x = event.getX();
		int layoutIndex = pixmap.findLayoutAt(y);
		Address layoutAddress = pixmap.getLayoutAddress(layoutIndex);
		if (layoutAddress == null) {
			return null;
		}

		List<String> lines = getMarkerTooltipLines(y, x, layoutIndex, layoutAddress);
		return toHTML(lines);
	}
Panel to display markers. Normally placed to the left hand side of the scrolled
{@link FieldPanel}.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/marker/MarkerPanel.java