public void itemExpanded(TreeItem item){
        if(item == tree.getRoot()){return;}
        
        expand(((FilePathTreeItem) item).getFilePath());
        
        for(int i=0; i<item.getChildCount(); i++){
            FilePathTreeItem childItem = (FilePathTreeItem) item.getChildAt(i);
            if(childItem.isLeaf()){continue;}
            
            try{
                if(expanded.get(childItem.getFilePath())){
                    childItem.setExpanded(true);
                }
            } catch(NullPointerException e){}
        }
    }