private JViewport getViewport() {
		Container c = getParent();
		while (c != null) {
			if (c instanceof JViewport) {
				return (JViewport) c;
			}
			c = c.getParent();
		}
		return null;
	}
Notifies all FieldMouselisteners that the cursor position changed.
Ghidra/Framework/Docking/src/main/java/docking/widgets/fieldpanel/FieldPanel.java