Unplanned
Last Updated: 02 Jun 2025 14:15 by Marvin

The scenario involves a DropDownList, which receives its data through OnRead at runtime asynchronously. The initial OnRead event that the component fires is not used, so the app calls Rebind() at some point. In this case, the component Value doesn't display until the user opens the dropdown. A possible workaround is to set the Value after the OnRead execution is complete.

https://blazorrepl.telerik.com/mfuUkwFR07p1jyo113

Completed
Last Updated: 23 May 2025 08:33 by ADMIN
Release 9.0.0
Opening the DDL through the expand button and selecting an item results in focus loss
Completed
Last Updated: 23 May 2025 08:33 by ADMIN
Release 9.0.0
Completed
Last Updated: 23 May 2025 08:33 by ADMIN
Release 9.0.0
Created by: Denver
Comments: 0
Category: DropDownList
Type: Bug Report
4
On a tablet, when the DropDownList, the MultiSelect or the ComboBox components are clicked, any appearance or disappearance of the tablet keyboard will cause them to display an empty popup.

This only happens if the popup somehow could otherwise overflow the viewport, i.e. only when the DropDownList, the MultiSelect or the ComboBox component are very close to the bottom of the viewport.
Completed
Last Updated: 23 May 2025 08:33 by ADMIN
Release 9.0.0
I have added a Filterable DropDownList inside the TelerikForm. When I select a value from the popup and tab away the focus class still denotes that the component is focused even though it is not. 
Completed
Last Updated: 23 May 2025 08:33 by ADMIN
Release 9.0.0
The DropDownList is not opening after pressing the small arrow to the far right of the input box on a mobile device. The DropDownList always opens if you click specifically on the text. However, after selection, if you click the arrow and not the text, the DropDownList will not open, and it breaks and you can no longer open the DropDownList even if you select the text.
Planned
Last Updated: 13 May 2025 05:16 by ADMIN
Scheduled for 2025 Q3 (Aug)
Created by: Indra
Comments: 2
Category: DropDownList
Type: Bug Report
7

I have a cascading DropDownList scenario with virtual scrolling. When the first DropDownList changes value, the second one should reset its scrollbar to the top, because it now contains new data. This doesn't happen.

Here is a REPL test page.

===

ADMIN EDIT

===

As a workaround for the time being, you may track when the value is changed in the parent DropDownList to dispose and re-initialize the child DropDownList.

Here is an example: https://blazorrepl.telerik.com/mdafHabk585ZtzyV54.

Unplanned
Last Updated: 25 Mar 2025 09:28 by Sebastian

The problematic behavior can be reproduced in the following case:

  • The DropDownList is at the lower part of the page, so the popup is rendered on top of the main element.
  • The popup height is set to "auto".

In this scenario, when the user filters, the popup position remains unchanged but its height is reduced to fit the filter results. Thus, the popup looks detached from the main element. The behavior is not the same when the popup is rendered below the main element as in this case its top part sticks to the main element.

Reproduction: https://blazorrepl.telerik.com/mpEHGzOt25F1Znxi57.

===

ADMIN EDIT

===

As a workaround for the time being, you can ensure that the popup has a fixed height, so it does not collapse when there are less items to show. You may keep the default popup height or set your desired one through the settings tag. For example: https://blazorrepl.telerik.com/mpYdcfaN38JvIHgP41.
Unplanned
Last Updated: 24 Mar 2025 12:25 by n/a

The DropDownList is supposed to open the popup element when Alt-Down is pressed. This doesn't work if the page itself scrolls. Pressing alt-down scrolls the page instead. This is on macOS Safari and Chrome on a MacBook.

https://demos.telerik.com/blazor-ui/dropdownlist/keyboard-navigation

Completed
Last Updated: 12 Feb 2025 16:02 by ADMIN
Release 8.0.0
The validation Tooltip does not show correctly when hovering from the icon to the select element in the DropDownList
Completed
Last Updated: 09 Dec 2024 09:23 by ADMIN
Release 2025 Q1 (Feb)

Here is the scenario:

  • A select component is near the bottom of the screen and its dropdown shows above the component.
  • Height="auto" is set in the PopupSettings
  • Filtering is enabled.
  • Component version 6.1.0 or later

In this case, reducing or increasing the number of visible dropdown items does not adjust the open dropdown's position. As a result, it may either float too high, or overflow the screen.

Possible workarounds are:

  • Use a fixed height in the PopupSettings.
  • Downgrade to version 6.0.2.

Here is a test page:

<div style="height:80vh;background:linear-gradient(white,orange)">
    <ol>
        <li>Open a ComboBox</li>
        <li>Type a character to filter and reduce the visible data items</li>
        <li>Observe incorrect popup position that leaves a gap</li>
    </ol>
    <ol>
        <li>Focus a closed ComboBox</li>
        <li>Type a character to filter and display a reduced list of data items</li>
        <li>Remove the filter string to increase the visible data item count</li>
        <li>Observe incorrect popup position that overflows the screen</li>
    </ol>
</div>

WORKS:
<TelerikComboBox Data="@ListItems"
                 @bind-Value="@SelectedValue"
                 TextField="@nameof(ListItem.Text)"
                 ValueField="@nameof(ListItem.Id)"
                 Filterable="true"
                 FilterOperator="@StringFilterOperator.Contains"
                 Width="300px" />

BROKEN:
<TelerikComboBox Data="@ListItems"
                 @bind-Value="@SelectedValue"
                 TextField="@nameof(ListItem.Text)"
                 ValueField="@nameof(ListItem.Id)"
                 Filterable="true"
                 FilterOperator="@StringFilterOperator.Contains"
                 Width="300px">
    <ComboBoxSettings>
        <ComboBoxPopupSettings Height="auto" MinHeight="50px" MaxHeight="60vh" />
    </ComboBoxSettings>
</TelerikComboBox>

<div style="height:80vh;background:linear-gradient(orange, white)">

</div>

@code {
    private List<ListItem> ListItems { get; set; } = new();

    private int SelectedValue { get; set; }

    protected override void OnInitialized()
    {
        ListItems = new List<ListItem>();

        for (int i = 1; i <= 50; i++)
        {
            ListItems.Add(new ListItem()
            {
                Id = i,
                Text = $"Item {i} {(char)Random.Shared.Next(65, 91)}{(char)Random.Shared.Next(65, 91)}{(char)Random.Shared.Next(65, 91)}{(char)Random.Shared.Next(65, 91)}"
            });
        }

        base.OnInitialized();
    }

    public class ListItem
    {
        public int Id { get; set; }
        public string Text { get; set; } = string.Empty;
    }
}

 

Completed
Last Updated: 14 Nov 2024 09:25 by ADMIN
Release 7.0.0
When I place a DropDownList inside a Modal Window and run it in Safari there is a flicker in the UI when the dropdown is expanded.
Unplanned
Last Updated: 09 Oct 2024 10:43 by Brian

When you select a date in DropDownList with dates in it (List<DateTime>), the @bind-Value is shaving off the milliseconds.

 

===ADMIN EDIT===

In the meantime, as a workaround for displaying milliseconds correctly, you can bind the DropDownList to a model. This way, you can use the "Id" to retrieve the selected item and display its precise milliseconds. Below is an example I've prepared to demonstrate this approach:

Selected value: @myDdlData.ToList().Where(x => x.Id == selectedValueId).FirstOrDefault()?.MyValueField.ToString("MM/dd/yyyy HH:mm:ss.fff")
<br />

<TelerikDropDownList Data="@myDdlData" 
                     TextField="MyTextField" 
                     ValueField="Id" 
                     @bind-Value="selectedValueId">
</TelerikDropDownList>

@code {
    public class MyDdlModel
    {
        public int Id { get; set; }
        public DateTime MyValueField { get; set; }
        public string MyTextField => MyValueField.ToString("MM/dd/yyyy HH:mm:ss.fff"); // Display formatted DateTime
    }

    private int selectedValueId { get; set; } = 1;

    private IEnumerable<MyDdlModel> myDdlData = GenerateRandomDateTimes(20);

    private static IEnumerable<MyDdlModel> GenerateRandomDateTimes(int count)
    {
        Random random = new Random();
        DateTime startDate = DateTime.Now;

        return Enumerable.Range(1, count)
            .Select(x => new MyDdlModel
            {
                Id = x, // Unique integer Id
                MyValueField = startDate.AddDays(x)
                    .AddMinutes(random.Next(0, 60))
                    .AddSeconds(random.Next(0, 60))
                    .AddMilliseconds(random.Next(0, 1000))
            }).ToList();
    }
}

Unplanned
Last Updated: 08 Oct 2024 13:12 by Shannon
Created by: Shannon
Comments: 0
Category: DropDownList
Type: Bug Report
1

The OnClose event fires multiple times when the handler uses the DialogFactory.

The behavior occurs with all select components (AutoComplete, ComboBox, DropDownList, MultiColumnComboBox, MultiSelect)

Possible workarounds include:

  • Use a boolean flag to prevent the OnClose handler from executing the second time, for example, if the second execution occurs less than 1-2 seconds after the first one.
  • Use OnChange instead of OnClose.
  • Use a <TelerikDialog> component instead of ConfirmAsync.

Here is a test page that reproduces the issue:

<div style="display: flex; gap: 2em;">
    <div>
        <TelerikButtonGroup SelectionMode="@ButtonGroupSelectionMode.Single">
            <ButtonGroupToggleButton @bind-Selected="@UseOnChange">Use OnChange</ButtonGroupToggleButton>
            <ButtonGroupToggleButton @bind-Selected="@UseOnClose">Use OnClose</ButtonGroupToggleButton>
        </TelerikButtonGroup>

        <TelerikDropDownList Data="@Data"
                             @bind-Value="@Value"
                             ValueField="@nameof(SampleModel.Text)"
                             OnChange="@OnDropDownListChange"
                             OnClose="@OnDropDownListClose"
                             Width="160px" />

    </div>
    <div>
        <TelerikButton OnClick="@( () => CloseLog = string.Empty )">Clear Event Log</TelerikButton>
        <p>
            <pre>@CloseLog</pre>
        </p>
    </div>
</div>

@code {
    private List<SampleModel> Data { get; set; } = new();

    private string Value { get; set; } = string.Empty;
    private List<string> Values { get; set; } = new();

    private string CloseLog { get; set; } = string.Empty;

    private bool UseOnClose { get; set; } = true;
    private bool UseOnChange { get; set; }

    [CascadingParameter]
    public DialogFactory? TelerikDialogs { get; set; }

    private async Task OnDropDownListChange(object currentValue)
    {
        CloseLog += $"OnChange {DateTime.Now.ToString("HH:mm:ss.fff")} \n";

        if (UseOnChange)
        {
            await TelerikDialogs!.AlertAsync("OnChange");
        }
    }

    private async Task OnDropDownListClose(DropDownListCloseEventArgs args)
    {
        CloseLog += $"OnClose {DateTime.Now.ToString("HH:mm:ss.fff")} \n";

        if (UseOnClose)
        {
            await TelerikDialogs!.AlertAsync("OnClose");
        }
    }

    public class SampleModel
    {
        public int Id { get; set; }
        public string Text { get; set; } = string.Empty;
    }
}

Completed
Last Updated: 05 Aug 2024 13:31 by ADMIN
Release 6.1.0
Created by: Matthijs
Comments: 4
Category: DropDownList
Type: Bug Report
6

Steps to reproduce:

  1. Open the Edit in Telerik REPL link from the demo page for DropDownList - Grouping.
  2. Add Filterable="true" to TelerikDropDownList.
  3. Run.
  4. Open the dropdown.
  5. Type in for instance the last item of the list "Röd Kaviar", that belongs to the category "Seafood".

Expected: the group name should change to "Seafood".

Actual: the group name is still "Beverages".

Duplicated
Last Updated: 11 Jun 2024 09:16 by ADMIN

When using the grouped DropDownList and performing a search for a specific element, the DropDownList incorrectly displays the initially shown group instead of the group containing the searched element.

To reproduce the issue: 

1. Open this REPL example: https://blazorrepl.telerik.com/QROrkouK40PFQCUU27
2. Open the DropDownList and type "v" in the filter input field.
Unplanned
Last Updated: 05 Jun 2024 10:06 by David
Created by: David
Comments: 0
Category: DropDownList
Type: Bug Report
9

In TelerikSelectBase that the DropDownList inherits, the FieldIdentifier is set only in the OnInitializedAsync method and therefore the FieldIdentitier is never updated. This can cause issues with validation as seen in this example:  https://blazorrepl.telerik.com/GyamPdlf37LXpPAW36.

To reproduce:

  • Select the last item in the tree 7.Garden and change the value in the drop down list to Unsupported - the drop down list shows a red border.
  • Select item 6.Garden from the tree. (Any item in the tree other than 1 will do) - I expect the drop down to not have the red border, yet is does.

For reference, in the TelerikInputBase, the FieldIdentifier is set in the SetParameterAsync and thus it is accordingly updated. See the TextBox behavior in the above sample.

Duplicated
Last Updated: 27 Mar 2024 16:05 by ADMIN

TlerikDropDownList keyboard navigation works differently from native html select.

In case we have a list with many similar options, for example:
011
021
211
....
In this case with native html select I can type 02 to select 021, but with TlerikDropDownList this would select 211.

If you type swiftly multiple printable characters, the DropDownList keyboard navigation will react only to the first character.

Completed
Last Updated: 17 Oct 2023 12:28 by ADMIN
Release 5.0.0 (15 Nov 2023) (R1 PI1)

Hi!

When i use combination of LINQ inside TelerikDropDownLists Data attribute and TelerikGrid 's GridEditMode.Popup mode, i get weird behavior when i try to select an item from TelerikDropDownLists - everything freezes. Please check the solution. Everything works fine if i don't use LINQ or GridEditMode.Popup mode.

 

Thank you!

Completed
Last Updated: 28 Sep 2023 14:41 by ADMIN
Release 4.6.0 (11 Oct 2023) (R3 2023)

Using DropDownList with Filter enabled will lost track of Focus when an item from dropdown is selected or tabbing away from filter input.

Steps to reproduce:

  1. Open a DropDownList with filter enabled
  2. Press TAB

Expected Behavior:

Focus in the next focusable element

Actual Behavior:

Focus is lost, and will go to the browser buttons

It is possible to reproduce in the demos:

https://demos.telerik.com/blazor-ui/dropdownlist/filtering

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