Be default, the card height is adjusted to fit the card content.

Auto card height enabled

html5 kanban card auto height enabled

Auto card height disabled

html5 kanban card auto height disabled

You can disable this behavior using CardAutoHeight property.

JavaScript

<div><label for="autoheight"><input type="checkbox" id="autoheight" checked="checked" /> Enable card auto height</label></div>

<div id="dp"></div>

<script type="text/javascript">

    var dp = new DayPilot.Kanban("dp");
    dp.columns.list = [
        {name: "Analysis", id: "1", barColor: "#f9ba25"},
        {name: "Draft", id: "2"},
        {name: "Testing", id: "3"}
    ];
    dp.cards.list = [
        {id: 1, "name": "Task 1", column: "1", text: "This is a description of task #1."},
        {id: 2, "name": "Task 2", column: "1", text: "This is a description of task #2. Testing a task with very long text. Testing a task with very long text. Testing a task with very long text. Testing a task with very long text. Testing a task with very long text. Testing a task with very long text. Testing a task with very long text. Testing a task with very long text."},
    ];
    dp.init();

    $(document).ready(function() {
        $("#autoheight").change(function() {
            dp.cardAutoHeight = $(this).is(":checked");
            dp.update();
        })
    });

</script>