@Override
	public void programSelectionChanged(ProgramSelection newP2Selection, EventTrigger trigger) {
		if (trigger != EventTrigger.GUI_ACTION) {
			return;
		}
		setProgram2Selection(newP2Selection);
	}
Callback when user changes selection in the program2 diff panel.

Note: A P2 selection is handed to this method when a selection is made in the diff listing
which displays P2.
Ghidra/Features/ProgramDiff/src/main/java/ghidra/app/plugin/core/diff/ProgramDiffPlugin.java