Buttons

public static ButtonNode[] bn = null;

void OnGUI()
{
    GUILayout.BeginHorizontal();

    if (bn == null)
    {
        bn = new ButtonNode[10];
        for (int i = 0; i < bn.Lenght; ++i)
        {
            bn[i] = new ButtonNode();
        }
    }

    for (int i = 0; i < bn.length; i++)
    {
        // this line has to be removed, to avoid recreation of buttons
        // bn[i] = new ButtonNode();
        if (bn[i].button = GUILayout.Button(bn[i].name + i, GUILayout.Width(bn[i].sizeW)))
        {
            bn[i].AlterButton();
        }
    }

    GUILayout.EndHorizontal();
}