Select2 Not Working in Bootstrap Modal During Remote Desktop Session, Works Locally

I’m encountering an issue where Select2 dropdowns do not work correctly when used in a Bootstrap Modal during a Remote Desktop Session (RDP). However, the same functionality works perfectly when accessed locally.

Problem Description

I have a form within a Bootstrap modal that uses Select2 for dropdowns. When users access the application locally (directly on the machine), everything works as expected. However, when accessing it through an RDP session, Select2 fails:

• The dropdown doesn’t open or doesn’t respond to clicks.
• Sometimes the dropdown appears outside the visible area or behind other elements.
• Input events like typing or clicking don’t seem to be registered properly.

Technical Details

Frontend libraries:

• Bootstrap 5.2
• Select2 v4.1

Server environment: Windows Server 2019 with Remote Desktop Services (RDS) enabled.

Client environment: Windows 10/11, using the standard Remote Desktop Client (mstsc.exe).

Browsers: The issue persists in Chrome, Edge, and Firefox during RDP sessions.

What Have We Tried?

1. Disabling modal focus enforcement:

    $('#myModal').modal({
        backdrop: 'static',
        keyboard: false,
        focus: false
    });

2. Adjusting dropdown positioning: Configuring dropdownParent to ensure the dropdown renders inside the modal:

    $('.select2').select2({
        dropdownParent: $('#myModal')
    });

3. Reinitializing Select2 on modal show: Destroying and reinitializing Select2 when the modal opens:

$('#myModal').on('shown.bs.modal', function() {
    $('.select2').select2('destroy').select2({
        dropdownParent: $(this)
    });
});

4. Adjusting z-index and CSS: Increasing the z-index of the Select2 container to prevent rendering issues:

.select2-container {
    z-index: 1055; /* Ensures it appears above other elements */
}

5. Testing simpler alternatives: Using a standard HTML element without Select2 works without any issues, indicating the problem is specific to Select2.

6. Modifying RDP settings:

Enabled hardware acceleration on both the RDP server and client.

Disabled visual effects such as compression and graphical optimizations.

7. Tried other dropdown libraries: Libraries like Choices.js work fine but don’t fully meet the requirements of the application.

Questions for the Community

• Are there known compatibility issues with Select2 in Remote Desktop Sessions?
• How can we ensure Select2 behaves consistently in an RDP environment?
• Are there specific configurations or workarounds to resolve focus or rendering issues in this scenario?

Additional Details

Here’s a simplified example of the modal and Select2 setup:

<div id="myModal" class="modal fade" tabindex="-1" role="dialog">

    <div class="modal-dialog">

        <div class="modal-content">

            <div class="modal-header">

                <h5 class="modal-title">Form</h5>

                <button type="button" class="btn-close" data-bs-dismiss="modal" aria-label="Close"></button>

            </div>

            <div class="modal-body">

                <form>

                    <label for="exampleSelect">Select an option:</label>

                    <select class="form-control select2" id="exampleSelect">

                        <option value="1">Option 1</option>

                        <option value="2">Option 2</option>

                        <option value="3">Option 3</option>

                    </select>

                </form>

            </div>

        </div>

    </div>

</div>

And the initialization for Select2:

$('.select2').select2({
    dropdownParent: $('#myModal')
});

Summary

It seems that Select2 has issues with focus or rendering when used in Bootstrap modals during RDP sessions. How can we resolve or work around this to make the functionality behave as expected in both environments?