public Object getActionContext(MouseEvent event) {
		ListingPanel panel = null;
		if (event != null) {
			Component c = (Component) event.getSource();
			if (c instanceof FieldHeaderComp) {
				return listingPanels[0].getFieldHeader().getFieldHeaderLocation(event.getPoint());
			}
			for (int i = 0; i < 4; i++) {
				if (listingPanels[i].getFieldPanel() == c) {
					panel = listingPanels[i];
					break;
				}
			}
		}
		if (panel == null) {
			panel = listingPanels[currProgIndex];
		}
		if (panel != null) {
			return panel.getProgramLocation();
		}
		return null;
	}
@see java.awt.event.FocusListener#focusLost(java.awt.event.FocusEvent)
Ghidra/Features/Base/src/main/java/ghidra/app/merge/tool/ListingMergePanel.java