setCellEditor of ui.spreadsheet, Methods Webix Docs

$$("ss1").setCellEditor(8, 1, { 
    editor: "ss_richselect", 
    options: ["One", "Two", "Three"] 
   }, "Sheet1");
 
// or
$$("ss1").setCellEditor(8, 2, { 
    editor:"ss_richselect", 
    options:"B3:B7", 
    empty:true 
   }, "Sheet1");

You can pass null as the editorObject parameter. In this case the editor will be removed from the cell.