public boolean hasSelectedLinkedNodes() {
		ProjectIndexService projectIndex = getComponentProvider().getProjectIndex();
		for (FSBNode node : getSelectedNodes()) {
			DomainFile df = projectIndex.findFirstByFSRL(node.getFSRL());
			if (df != null) {
				return true;
			}
		}
		return false;
	}
Returns the FSRL of the currently selected item, if it is a 'loadable' item.

@return FSRL of the currently selected loadable item, or null if nothing selected or
more than 1 selected
Ghidra/Features/Base/src/main/java/ghidra/plugins/fsbrowser/FSBActionContext.java