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function onOpen(e) {
  SpreadsheetApp.getUi()
  .createMenu('Scripts')
  .addItem('Multi-select for this cell...', 'showDialog')
  .addToUi();
}
function showDialog() {  
  var html = HtmlService.createHtmlOutputFromFile('dialog').setSandboxMode(HtmlService.SandboxMode.IFRAME);
  SpreadsheetApp.getUi()
  .showSidebar(html);
}
function getValidationData(){
  try {
    return SpreadsheetApp.getActiveRange().getDataValidation().getCriteriaValues()[0].getValues();
  } catch(e) {
    return null
  }
}

function setValues_(e, update) {
  var selectedValues = [];
  
  for (var i in e) {
    selectedValues.push(i);
  }
  var separator = '\n'
  var total = selectedValues.length
  if (total > 0) {
    var range = SpreadsheetApp.getActiveRange()
    var value = selectedValues.join(separator)
    if (update) {
      var values = range.getValues()
      // check every cell in range
      for (var row = 0; row < values.length; ++row) {
        for (var column = 0; column < values[row].length; ++column) {
          var currentValues = values[row][column].split(separator);//typeof values[row][column] === Array ? values[row][column].split(separator) : [values[row][column]+'']
          // find same values and remove them
          var newValues = []
          for (var j = 0; j < currentValues.length; ++j) {
            var uniqueValue = true
            for(var i = 0; i < total; ++i) {
              if (selectedValues[i] == currentValues[j]) {
                uniqueValue = false
                break
              }
            }
            
            if (uniqueValue && currentValues[j].trim() != '') {
              newValues.push(currentValues[j])
            }
          }
          
          if (newValues.length > 0) {
            range.getCell(row+1, column+1).setValue(newValues.join(separator)+separator+value)
          } else {
            range.getCell(row+1, column+1).setValue(value);
          }
        }
      }
    } else {
      range.setValue(value);
    }
  }
}

function updateCell(e) {
  return setValues_(e, true)
}

function fillCell(e) {
  setValues_(e)
}