According to GAS documentation, we can use this methods to insert a dropdownlist in a sheet cell:
var cell = SpreadsheetApp.getActive().getRange('A1');
var rule = SpreadsheetApp.newDataValidation().requireValueInList(['Yes', 'No'], false).build();
cell.setDataValidation(rule);
I'd like to know if there is a way to insert not a dropdown list, but dropdown a checkbox list in cell, in a similar fashion of requireValueInList
when some trigger is used (eg, when the first cell of that row is edited).