Hello Sheeba,

Maybe one possible approach to achieve the desired behavior is by using a UltraControlContainerEditor.  For example:

public partial class Form1 : Form
{
    UltraComboEditor uc = new UltraComboEditor();
    UltraComboEditor uc2 = new UltraComboEditor();
 
    public Form1()
    {
        InitializeComponent();
 
        this.ultraTree1.Override.ShowEditorButtons = ShowEditorButtons.Always;
        this.ultraTree1.Override.LabelEdit = Infragistics.Win.DefaultableBoolean.True;
        this.ultraTree1.Override.UseEditor = DefaultableBoolean.True;
 
 
        UltraControlContainerEditor ucc = new Infragistics.Win.UltraWinEditors.UltraControlContainerEditor();
 
        DataTable dt = new DataTable("Tabl");
        dt.Columns.Add("Y", typeof(String));
        dt.Rows.Add( "Test A");
        dt.Rows.Add("Test B");
        dt.Rows.Add("Test C");
        dt.Rows.Add("Test D");
 
        uc2.DropDownStyle = DropDownStyle.DropDownList;
        uc.DropDownStyle = DropDownStyle.DropDownList;
        uc2.DataSource = dt;
        uc.DataSource = dt;
 
        ucc.RenderingControl = uc2;
        ucc.EditingControl = uc;
        this.ultraTree1.NodeLevelOverrides[1].EditorComponent = ucc;
    }
}

Please take a look at the attached sample for more details. Please let me know if you have any questions.