Thanks Cetin,
But that not work in the following way:
In InteractiveChange of the TextBox:

SEEK UPPER(this.Value) IN MyTable ORDER MyOrder
IF FOUND()
   thisform.OleTree.SelectedItem.BackColor = RGB(255,255,255)
   thisform.OleTree.SelectedItem.ForeColor = RGB(0,0,0)
   thisform.OleTree.SelectedItem = thisForm.OleTree.Nodes(ALLTRIM(STR(MyTable.Kod))+"_")
   thisform.OleTree.NodeClick(thisform.OleTree.SelectedItem) && In that method I populate a view based of the field Kod
   thisform.OleTree.SelectedItem.BackColor = RGB(255,0,0)
   thisform.OleTree.SelectedItem.ForeColor = RGB(255,255,255)
   thisform.OleTree.Refresh()
ELSE
   ....
ENDIF