JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="https://s3.amazonaws.com/flexmonster/2.3/demo.css">
<script src="https://cdn.flexmonster.com/flexmonster.js"></script>

<div id="pivot-container"></div>

CSS

.notexpandable {
  cursor: initial;
}

JavaScript

let pivot = new Flexmonster({
  container: "pivot-container",
  componentFolder: "https://cdn.flexmonster.com/",
  toolbar: true,
  report: {
    "dataSource": {
      "filename": "data/data.json"
    },
    "options": {
        "showReportFiltersArea": true,
        "showAllFieldsDrillThrough": true,
        "configuratorButton": true,
        "showDrillThroughConfigurator": true,
        "showFieldListSearch": true,
        "allowBrowsersCache": true,
        "grid": {
            "type": "classic",
            "title": "Ledger Details & Export",
            "showFilter": true,
            "showHeaders": false,
            "showTotals": "off",
            "showGrandTotals": "off"
        }
    },
    "slice": {
      "rows": [{
        "uniqueName": "Country"
      }, {
        "uniqueName": "Destination"
      },{
        "uniqueName": "Category"
      },{
        "uniqueName": "Color"
      }],
      "columns": [{
        "uniqueName": "[Measures]"
      }],
      "measures": [{
        "uniqueName": "Price"
      }],
      "expands": {
         "expandAll": true
      },
    },
  },
  reportcomplete: () => {
        flexmonster.off("reportcomplete");
        pivot.customizeCell(customizeCellFunction);
  }
});

function customizeCellFunction(cell, data) {
  if (data && data.type == "header" &&
      data.member && data.member.caption != 'All' &&
      data.label == "") {
    cell.text = data.member.caption;
  }
  
  if (data.hierarchy &&
    data.member ) {
    var parts = cell.text.split(data.escapedLabel);
    if (parts.length == 2) {
      cell.text = `<div class='notexpandable' onclick="preventExpand(event)"><div class='notexpandable' onclick="preventExpand(event)">${data.escapedLabel}</div>${parts[1]}</div>`;
    }
  }
}

function preventExpand(e) {
  e.stopImmediatePropagation();
}

function clearCustomizing() {
  pivot.customizeCell();
}

function startCustomizing() {
 // pivot.customizeCell(customizeCellFunction);
}

function clickHandler()...