You can customize the column menu icon by overriding the default Tree Grid class .e-icons.e-columnmenu with a custom property content as mentioned below,
.e-treegrid .e-columnheader .e-icons.e-columnmenu::before {
content: "\e903";
}
In the below sample, Tree Grid is rendered with a customized column menu icon.
ej.treegrid.TreeGrid.Inject(ej.treegrid.ColumnMenu);
var treeGrid = new ej.treegrid.TreeGrid({
dataSource: window.projectData,
idMapping: "TaskID",
parentIdMapping: "parentID",
treeColumnIndex: 1,
height: 315,
showColumnMenu: true,
columns: [
{ field: "TaskID", headerText: "Task ID", textAlign: "Right", width: 70 },
{ field: "TaskName", headerText: "Task Name", width: 100 },
{ field: "StartDate", headerText: "Start Date", textAlign: "Right", width: 90,
format: { skeleton: "yMd", type: "date" } },
{ field: "EndDate", headerText: "End Date", textAlign: "Right", width: 90,
format: { skeleton: "yMd", type: "date" } },
{ field: "Duration", headerText: "Duration", textAlign: "Right", width: 90 },
{ field: "Priority", headerText: "Priority", width: 90 }
]
});
treeGrid.appendTo("#TreeGrid");
#container {
visibility: hidden;
}
#loader {
color: #008cff;
font-family: 'Helvetica Neue','calibiri';
font-size: 14px;
height: 40px;
left: 45%;
position: absolute;
top: 45%;
width: 30%;
}
.e-treegrid .e-columnheader .e-icons.e-columnmenu::before {
content: "\e903";
}
<!DOCTYPE html><html lang="en"><head>
<title>EJ2 Grid</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta name="description" content="Typescript Grid Control">
<meta name="author" content="Syncfusion">
<link href="index.css" rel="stylesheet">
<link href="//cdn.syncfusion.com/ej2/ej2-base/styles/material.css" rel="stylesheet">
<link href="//cdn.syncfusion.com/ej2/ej2-grids/styles/material.css" rel="stylesheet">
<link href="//cdn.syncfusion.com/ej2/ej2-treegrid/styles/material.css" rel="stylesheet">
<link href="//cdn.syncfusion.com/ej2/ej2-buttons/styles/material.css" rel="stylesheet">
<link href="//cdn.syncfusion.com/ej2/ej2-popups/styles/material.css" rel="stylesheet">
<link href="//cdn.syncfusion.com/ej2/ej2-navigations/styles/material.css" rel="stylesheet">
<link href="//cdn.syncfusion.com/ej2/ej2-dropdowns/styles/material.css" rel="stylesheet">
<link href="//cdn.syncfusion.com/ej2/ej2-lists/styles/material.css" rel="stylesheet">
<link href="//cdn.syncfusion.com/ej2/ej2-inputs/styles/material.css" rel="stylesheet">
<link href="//cdn.syncfusion.com/ej2/ej2-calendars/styles/material.css" rel="stylesheet">
<link href="//cdn.syncfusion.com/ej2/ej2-splitbuttons/styles/material.css" rel="stylesheet">
<script src="https://cdn.syncfusion.com/ej2/dist/ej2.min.js" type="text/javascript"></script>
<script src="es5-datasource.js" type="text/javascript"></script>
</head>
<body>
<div id="container">
<div id="TreeGrid"></div>
</div>
<script>
var ele = document.getElementById('container');
if(ele) {
ele.style.visibility = "visible";
}
</script>
<script src="index.js" type="text/javascript"></script>
</body></html>