@Override
	public void actionPerformed(ActionEvent e) {

		// Now fire off an event to any subscribers.
		FVEvent decrementEvt = new FVEvent(EventType.DECREMENT_AND_ADD_SELECTION, 1);
		eventListener.send(decrementEvt);
	}
The up arrow should move the selection up one row. Just fire off an event to tell the
viewer to decrement the selection, which may involve an adjustment to the viewport.
Ghidra/Framework/Project/src/main/java/ghidra/framework/main/logviewer/event/ArrowUpSelectionAction.java