Handle duplicate items - Githubissues

The library does not seem to be handling duplicate items in the list very well. Duplicate items are treated like the same items and ticking both items does not increment selection count. Un-ticking any of selected items removes both from the button.

My use-case for having duplicate items is with opt-groups, where item can belong to multiple groups.

Working example: https://jsbin.com/jisalukiyo

Example code:

<html lang="en">
<head>
    <meta charset="UTF-8">
    <link href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.4.1/css/bootstrap.min.css" rel="stylesheet">
    <link href="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-multiselect/0.9.15/css/bootstrap-multiselect.css" rel="stylesheet">
</head>
<body>
    <script src="//ajax.googleapis.com/ajax/libs/jquery/2.0.3/jquery.min.js"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.4.1/js/bootstrap.js"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-multiselect/0.9.15/js/bootstrap-multiselect.min.js"></script>

    <script type="text/javascript">
        $(document).ready(function() {
            $('select').multiselect();
        });
    </script>
    <div class="btn-group">
        <select multiple="multiple">
            <optgroup label="Group 1">
                <option value="1">Option 1</option>
            </optgroup>
            <optgroup label="Group 2">
                <option value="2">Option 2</option>
            </optgroup>
            <optgroup label="Everyone">
                <option value="1">Option 1</option>
                <option value="2">Option 2</option>
            </optgroup>
        </select>
    </div>
</body>
</html>

davidstutz / bootstrap-multiselect

Handle duplicate items #1093