Remove selected node from JTreeTable SwingX error

I am having a strange error when I am trying to remove selected node from JTreeTable. First of all, I get selected row in my main class from JXtreeTable

table.getSelectedRow()

I do it with this method, and it returns me a correct number of row. But then, shit happends. In my model class I call method delete children:

    package JTreeTable;

import org.jdesktop.swingx.treetable.AbstractMutableTreeTableNode;
import org.jdesktop.swingx.treetable.DefaultMutableTreeTableNode;
import org.jdesktop.swingx.treetable.DefaultTreeTableModel;
import org.jdesktop.swingx.treetable.MutableTreeTableNode;
import org.jdesktop.swingx.treetable.TreeTableModel;

public class TableModel extends DefaultTreeTableModel implements TreeTableModel {


    DefaultMutableTreeTableNode root;// = new DefaultMutableTreeTableNode("Root");

    public TableModel(DefaultMutableTreeTableNode root){
         super(root);//it didnt work without this line. it took me a day to figure it out. I hate my life sometimes.
         this.root = root;

    }

    public int getColumnCount() 
    {
        return 4;
    }

    @Override
    public String getColumnName( int column )
    {
        switch( column )
        {
        case 0: return "Description";
        case 1: return "Amount";
        case 2: return "Date";
        case 3: return "Paid";

        default: return "Unknown";
        }
    }

    public void addChildren(){
        int rootChildCount = root.getChildCount();
        ArrayNode newChild = new ArrayNode(new Object[] {"dfds", "sfddsf","dfsfsd","fdsfsd"});
        this.insertNodeInto(newChild, root, rootChildCount);
    }

    public void removeChildren(int index){
          //root.remove(index);
    System.out.println(root.getChildCount());   

    }

}

And here my node class:

package JTreeTable;

import org.jdesktop.swingx.treetable.AbstractMutableTreeTableNode;
import org.jdesktop.swingx.treetable.DefaultMutableTreeTableNode;

public class ArrayNode extends DefaultMutableTreeTableNode {

    public ArrayNode(Object[] data) {
        super(data);
    }

    @Override
    public Object getValueAt(int column) {
        return getUserObject()[column];
    }

    @Override
    public void setValueAt(Object aValue, int column) {
        getUserObject()[column] = aValue;
    }

    @Override
    public int getColumnCount() {
        return 4;
    }

    @Override
    public Object[] getUserObject() {
        return (Object[]) super.getUserObject();
    }

    @Override
    public boolean isEditable(int column) {
        return true;
    }

}

So, when i use method root.remove(index) i always get error "Node must be a valid node managed by this model". But i am pretty sure my nodes are ok! What this means and is it fixable?

You are trying to remove the child directly from another node, bypassing the TreeTableModel. Use DefaultTreeTableModel.removeNodeFromParent, e.g:

public void removeChildren(int index) {
    MutableTreeTableNode node = root.getChildAt(index);
    this.removeNodeFromParent(node);
}