private void createSelection(Navigatable navigatable) {
		ProgramLocation location = navigatable.getLocation();
		Address start = markedLocation.getByteAddress();
		Address end = location.getByteAddress();
		ProgramSelection selection = new ProgramSelection(start, end);
		navigatable.setSelection(selection);

		// set back to unarmed
		markedLocation = null;
		markedNavigatable = null;
	}
Actions for creating a selection using two distinct steps. The first time the action is invoked,
it records the current location as the start of a selection. The second time the action is
invoked it creates a selection from the recorded location to the current location.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/codebrowser/MarkAndSelectionAction.java