Treechildren contains a collection of treeitem components. It is main body of the Tree and it also the main body of a Treeitem's children.

You can change the page size of each treechildren instance by modifying the pageSize property

<window title="tree demo" border="normal" width="450px">
    <tree id="tree" width="90%" >    
        <treecols sizable="true">        
            <treecol label="Name"/>            
            <treecol label="Description"/>            
        </treecols>        
        <treechildren>        
            <treeitem>            
                <treerow>                
                    <treecell label="Item 1"/>                    
                    <treecell label="Item 1 description"/>                    
                </treerow>                
            </treeitem>            
            <treeitem>            
                <treerow>                
                    <treecell label="Item 2"/>                    
                    <treecell label="Item 2 description"/>                    
                </treerow>                
                <treechildren>                
                    <treeitem>                    
                        <treerow>                        
                            <treecell label="Item 2.1"/>                            
                        </treerow>                        
                        <treechildren pageSize="3">                        
                            <treeitem>                            
                                <treerow>                                
                                    <treecell label="Item 2.1.1"/>                                    
                                </treerow>                                
                            </treeitem>                            
                            <treeitem>                            
                                <treerow>                                
                                    <treecell label="Item 2.1.2"/>                                    
                                </treerow>                                
                            </treeitem>                            
                            <treeitem>                            
                                <treerow>                                
                                    <treecell label="Item 2.1.3"/>                                    
                                </treerow>                                
                            </treeitem>                            
                            <treeitem>                            
                                <treerow>                                
                                    <treecell label="Item 2.1.4"/>                                    
                                </treerow>                                
                            </treeitem>                            
                        </treechildren>                        
                    </treeitem>                    
                    <treeitem>                    
                        <treerow>                        
                            <treecell label="Item 2.2"/>                            
                            <treecell label="Item 2.2 is something who cares"/>                            
                        </treerow>                        
                    </treeitem>                    
                </treechildren>                
            </treeitem>            
            <treeitem label="Item 3"/>            
        </treechildren>        
    </tree>    
</window>