@Override
	public void selectionChanged(FieldSelection selection, EventTrigger trigger) {
		if (listingModel == null) {
			// Dragging in a popup window that contains a listing while that window
			// closes can trigger this condition
			return;
		}

		String text = FieldSelectionHelper.getFieldSelectionText(selection, fieldPanel);
		if (stringSelectionListener != null) {
			stringSelectionListener.setStringSelection(text);
		}

		currentTextSelection = text;
		if (text != null) {
			return;
		}

		if (listingModel.getProgram() == null || programSelectionListener == null) {
			return;
		}
		ProgramSelection ps = layoutModel.getProgramSelection(selection);
		if (ps != null) {
			programSelectionListener.programSelectionChanged(ps, trigger);
		}
	}
Sets the highlight.

@param highlight the new highlight.
Ghidra/Features/Base/src/main/java/ghidra/app/util/viewer/listingpanel/ListingPanel.java