Robot Framework - Unable to find filter xpath in Kendo grid and add text

I am attempting to create a Robot Framework Selenium test where I input text into a Kendo grid filter and then check the results. The grid is here:

The filter code is here:

<thead class="k-grid-header" xpath="1">
  <tr>...</tr>
  <tr>
    <td class="rowFilterContainer"></td>
    <td class="rowFilterContainer"></td>
    <td class="rowFilterContainer" data-field="UserId"></td>
    <td class="rowFilterContainer" data-field="CandidateId">
      <input class="rowFilter" data-field="CanddateId" data-type="string" type="text" data- 
      operator="startswith">
    </td>

I am attempting to locate and then enter text in the CandidateId field using Selenium with an xpath of "//div[@id='Tab_0']//td[4]//input[1]" but when I run the test if complains that it cannot find it.

Any help on how to find this field (with a better xpath) and to add the text would be greatly appreciated. I have tried using CSS as well.