Completed
Last Updated: 16 Jun 2025 14:04 by ADMIN
Created by: Amanatios Amanatidis
Comments: 0
Category: ToolBar
Type: Bug Report
3

Description

Adaptive Toolbar buttons do not appear in the overflow popups when expected.

Steps To Reproduce

https://demos.telerik.com/blazor-ui/toolbar/adaptive

https://blazorrepl.telerik.com/mTuAEzPe41y4e7y637

Use the slider to reduce the witdh of the toolbars

Actual Behavior

Visible buttons that disappear from the toolbar do not appear in the two popups.

Expected Behavior

Visible buttons that disappear from the toolbar should appear in the overflow popup.

Browser

All

Last working version of Telerik UI for Blazor (if regression)

8.1.1

Completed
Last Updated: 16 Jun 2025 08:19 by ADMIN
Release 2025 Q3 (Aug)
Created by: Roman
Comments: 0
Category: Breadcrumb
Type: Bug Report
2

Description

When new data is loaded in the Breadcrumb, if at that moment some of the old items are hidden (because the browser window is too narrow), once the component visualizes the new data, the last item remains hidden.

Workaround
Add the following CSS to the page:

<style>
    .k-breadcrumb-last-item  {
        display: inline-block !important;
    }

    .k-breadcrumb-last-item .k-breadcrumb-link {
        display: inline-flex !important;
    }
</style>

Steps To Reproduce

  1. Run this REPL example: https://blazorrepl.telerik.com/QTEqFvve37kGQ8C743
  2. Ensure that the right pane is not too wide, in order for some of the Breadcrumb items to remain collapsed.
  3. Click the button above the Breadcrumb. New data that contains 2 items is loaded in the component.

Actual Behavior

The Breadcrumb's last item ("Breadcrumb B 2") is hidden.

Another issue reproducible after loading more than 2 items in the Button's click handler is the Breadcrumb begins to flicker on pane (browser window) resize. The flickering is caused by items showing/hiding almost at the same time.

Expected Behavior

The behavior should remain as it is on initial load. The first and last items should always be visible.

No flickering should occur and there should be a smooth transition between hiding and showing an item.

Browser

All

Last working version of Telerik UI for Blazor (if regression)

No response

Completed
Last Updated: 16 Jun 2025 08:19 by ADMIN
Release 2025 Q3 (Aug)

Hello:

I am using column menu in a gantt component. In version 8.1.1 the selection of columns to display was working correctly, but when upgrading to version 9.0.0 I get an error using the same implementation. The error received is:

blazor.web.js:1 crit: Microsoft.AspNetCore.Components.WebAssembly.Rendering.WebAssemblyRenderer[100]
      Unhandled exception rendering component: Object reference not set to an instance of an object.
System.NullReferenceException: Object reference not set to an instance of an object.
   at Telerik.Blazor.Components.Common.ColumnMenu.ColumnMenu`1.<OnColumnChooserColumnVisibilityChange>d__188[[BlazorRepl.UserComponents.__Main.FlatModel, BlazorRepl.UserComponents, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null]].MoveNext()
   at Telerik.Blazor.Components.Common.ColumnMenu.ColumnMenuChooser.OnApplyClick()
   at Microsoft.AspNetCore.Components.ComponentBase.CallStateHasChangedOnAsyncCompletion(Task task)
   at Microsoft.AspNetCore.Components.RenderTree.Renderer.GetErrorHandledTask(Task taskToHandle, ComponentState owningComponentState)

You can replicate the error from online examples just by adding or removing visible columns.
https://www.telerik.com/blazor-ui/documentation/components/gantt/gantt-tree/columns/menu

I need to use this functionality with TelerikĀ® UI for Blazor version 9.0.0.

When is it planned to solve this error? Is there a workaround I can apply?

Regards.

Completed
Last Updated: 12 Jun 2025 07:18 by ADMIN
Release 2025 Q3 (Aug)

The Expand/Collapse icon of the PivotGrid is always a font one. I am using SVG icons in my app and I don't see the any icon in the toggle button.

===

ADMIN EDIT

===

A workaround for the time being is to register the Font icons stylesheet even if you are using SVG icons.

Unplanned
Last Updated: 12 Jun 2025 06:48 by ADMIN

If you are zooming a page containing a DateTimePicker with "AdaptiveMode" set to "AdaptiveMode.Auto", the application crashes occasionally with the error:

Microsoft.JSInterop.JSException: Cannot read properties of null (reading 'addEventListener')
TypeError: Cannot read properties of null (reading 'addEventListener')

The more adaptive DateTimePicker instances the page contains, the more likely the error is to occur.

 

 

Completed
Last Updated: 11 Jun 2025 11:26 by ADMIN
Release 2025 Q3 (Aug)
Created by: Fabian
Comments: 0
Category: NumericTextBox
Type: Bug Report
1

Form validation triggers unexpectedly and too early when:

  • The Value is nullable.
  • ValidateOn is set to Change.
  • The user inputs a minus sign in an empty NumericTextBox.

Test page: https://blazorrepl.telerik.com/mzOUOolG385hImjN13

Unplanned
Last Updated: 09 Jun 2025 12:47 by ADMIN
Scheduled for 2025 Q3 (13.08.2025)

Steps to reproduce the behavior:

1. Create Blazor WebApp Net 8 6.2.0 project
2. Upgrade project to 7.1.0 version
3. On the Upgrade wizard validation step, see the error:

An error occurred while running the wizard.

Error executing custom action Telerik.Blazor.VSX.Actions.MultiProjectUpdateMasterPageAction: System.InvalidOperationException: Sequence contains no matching element
   at System.Linq.Enumerable.First[TSource](IEnumerable`1 source, Func`2 predicate)
   at Telerik.Blazor.VSX.Actions.AdvancedUpdateMasterPageAction.RetrieveMasterPageSettingsUpgradeInfo(IPropertyDataDictionary arguments, IProjectWrap project)
   at Telerik.Blazor.VSX.Actions.UpdateMasterPageAction.Execute(WizardContext wizardContext, IPropertyDataDictionary arguments, IProjectWrap projectWrap)
   at Telerik.VSX.Actions.ProjectActionBase.Telerik.VSX.Actions.IProjectAction.Execute(IWizardContext wizardContext, IPropertyDataDictionary arguments, IProjectWrap projectWrap)
   at Telerik.VSX.Actions.MultiProjectActionBase`1.Execute(WizardContext wizardContext, IPropertyDataDictionary arguments)
   at Telerik.VSX.WizardEngine.Actions.ActionBase.Telerik.WizardFramework.IAction.Execute(IWizardContext wizardContext, IPropertyDataDictionary arguments)
   at Telerik.VSX.WizardEngine.ActionManager.ExecActions()

Unplanned
Last Updated: 06 Jun 2025 14:14 by Amanatios Amanatidis

Description

TimePicker bound to a non-nullable DateTime property. User input is marked as invalid, when they change only part of the default TimePicker value.

Steps To Reproduce

  1. Run the following REPL example: https://blazorrepl.telerik.com/GpEUOflI50gehA9B54
  2. Focus the hour part of the input and type in a number, e.g., 3
  3. Blur the TimePicker

Actual Behavior

On beginning to type, the k-invalid class is applied to the TimePicker element. When the use clicks away, the current input value (e.g., 3:00 AM) is replaced with the default value (12:00 AM).

If you type the whole value (e.g., 3:45 AM) and then click away from the component, the k-invalid class is removed and the value is accepted as valid.

Expected Behavior

The k-invalid class should not be applied to the TimePicker in the scenario described above. The used should be able to change only the hour part of the value, or the minutes, without having to type in the whole value.

Browser

All

Last working version of Telerik UI for Blazor (if regression)

8.1.1

Unplanned
Last Updated: 06 Jun 2025 13:58 by Joe
Created by: Joe
Comments: 7
Category: UI for Blazor
Type: Bug Report
6
There is a date picker bug where if you change the value to something invalid (ex: backspace the date or a portion of it), it will still be bound to the previous date value selected. If you click the picker and select the same date again, it will not register it as a date change and will not fire the value changed event. This causes the field to still show as invalid. To the end-user, it looks as if there is a problem and is telling them it is invalid. I had a customer notice this and they kept trying to reselect the date but nothing would happen. 

They eventually typed it manually to fix, which is one way that I agree can be used to resolve. You can also select the wrong date, followed by the right date to get around, but that is a horrible workaround. 

What I believe the experience should be is that when selecting the value in the date picker, regardless of what it thinks is in the field, it should fire the change event and update the text of the field to the date selected (and clear the validation message). That is what I'd like to see as a future change. Note that this happens on ValueChanged, but not OnChanged. OnChanged fires too late though, and doesn't work for most workflows.

We put in a hack solution in some operator UIs where it is very important to not have this happen, but it is a pain to do this for every picker, so most in the system are unhandled. 

The solution was to have OnOpen and OnBlur both manually trigger ValueChanged (which ends up sending default - 1/1/1901) using a reference for the control. This helps us differentiate if it is these events vs an actual date change. When it is OnOpen/OnBlur, we then reupdate the value in the reference and refresh. Note that you end up having to do this twice to "trick" the telerik logic. So we change to default, refresh, and then change to the correct (or last good value - what is already bound) and refresh. Basically now when they leave the field or click the picker, if there is an invalid value and message, it clears and gets replaced with the last good date. If there is a valid date, it does nothing from the user perspective.  
Unplanned
Last Updated: 06 Jun 2025 13:18 by ADMIN
When we attach a document with non-standard size pages, incorrect page numbers are shown.
Planned
Last Updated: 06 Jun 2025 04:44 by ADMIN
Scheduled for 2025 Q3 (Aug)

When attempting to utilize the FilterMenuButtonsTemplate component, after selecting any of the defined action buttons (i.e., Clear, Filter, etc.), the selection will cause the page to refresh.

Steps:

  1. Proceed to the Telerik Blazor documentation page for Filter Menu Buttons Template within the Grid component.
  2. View the example for Using custom filter menu buttons.
  3. Ensure that this is the first time loading the component as the error will only occur on the example page when first initialized.
  4. Select the filter button within the ā€œPriceā€ column header.
  5. Press the ā€œClearā€ button.
In Development
Last Updated: 05 Jun 2025 13:42 by ADMIN
Scheduled for 2025 Q3 (Aug)
Created by: Alexander
Comments: 0
Category: FileManager
Type: Bug Report
2

The View Details tool of the FileManager throws a NullReferenceException when a file is selected. Folders do not trigger the error.

Affected versions as of writing this:

  • 8.1.0
  • 8.1.1
  • 9.0.0
Completed
Last Updated: 05 Jun 2025 12:25 by ADMIN
Release 2025 Q3 (Aug)
Created by: Stefan
Comments: 0
Category: Upload
Type: Bug Report
5

Description

File data is not available in the Upload's OnSuccess event.

Regression in version 9.0.0 introduced with the addition of the chunk upload functionality.

https://github.com/telerik/blazor/blob/master/js/telerik-blazor/src/upload/upload.ts#L282-L288

Steps To Reproduce

  1. Attach a handler to the OnSuccess event:
<TelerikUpload SaveUrl="/api/upload/save"
               RemoveUrl="/api/upload/remove"
               OnSuccess="@OnSuccessHandler" />

@code {
    async Task OnSuccessHandler(UploadSuccessEventArgs e)
    {
        foreach (var file in e.Files)
        {
            Console.WriteLine($"Name = {file.Name}, Size = {file.Size}, Extension = {file.Extension}");
        }

        StateHasChanged();
    }
}
  1. Upload a file and try to access its Name, Size, and Extension properties in the event handler.

Actual Behavior

The properties have their default values (null for Name and Extension and 0 for Size).

Expected Behavior

The actual file data is accessible in the OnSuccess event handler.

Browser

All

Last working version of Telerik UI for Blazor (if regression)

8.1.1

Unplanned
Last Updated: 04 Jun 2025 09:50 by ADMIN
Created by: Rami
Comments: 1
Category: MultiSelect
Type: Bug Report
1

I was hoping to use the new AllowCustom feature to let users name a few areas, save those names in the backend and later show them as preselected when the user comes back so they don't have to retype the names every time they do an operation. But alas, the AllowCustom seems to only allow preselecting from what's in the Data list of values.

So code like below doesn't actually show a chip for Rome even though it's preselected. There is a workaround of setting the Data property to a list that contains the custom values I need preselected, but it feels clumsy and with the custom values I feel Multiselect should also check the selected values list for chips to render.

<TelerikMultiSelect 
   @bind-Value="@SelectedCities"
   TItem="string" TValue="string"
   AllowCustom="true"                   
   Width="400px">
</TelerikMultiSelect>

<span>Selected: @SelectedCities.Count</span>

@code {
    private List<string> SelectedCities { get; set; } = new() {"Rome"};
}

Unplanned
Last Updated: 04 Jun 2025 08:11 by Linda

I have a splitter pane with 3 panels. If you resize the left panels (drag it back and forth), then the right panels incrementally increases in size. Similarly with anything more than 2 panels.

https://blazorrepl.telerik.com/GpOKaRFn37OSfEyp53

Grab any of the left splitters and drag them back and forth quickly. You will see the right panels increasing in size.

The problem occurs in Google Chrome when the pane Size is set in percent.

Completed
Last Updated: 03 Jun 2025 13:44 by ADMIN
Release 3.4.0

If the Grid has no data, selecting null PageSize throws:

Error: System.ArgumentException: Page Size cannot be less than one (Parameter 'PageSize') 

---

ADMIN EDIT

---

A possible workaround for the time being will be to use some conditional CSS to disable the PageSize dropdown while there is no data in the Grid: https://blazorrepl.telerik.com/QcOpkTlb38EDFboT34.

Unplanned
Last Updated: 02 Jun 2025 17:19 by David
In our serverside blazor application we use the Telerik's DateTimePicker. When we type values in to the date time picker control, it jumps to the next section or to the end before completing the currect section. We use the format 'yyyy-MM-dd HH:mm'

It does not happen always and I think it is happenning when the internet connection is slow and it shows a Javascript error as well (screenshots below)
Unplanned
Last Updated: 02 Jun 2025 14:33 by Lukasz
Created by: Lukasz
Comments: 0
Category: AutoComplete
Type: Bug Report
0

The AutoComplete DebounceDelay value is larger and the user is quick to type and blur the component, the dropdown will still open when this is no longer necessary.

A possible workaround is to cancel the Open event if it fires too soon after OnChange (uncomment the yellow line):

<p>Quickly type a number (1 - 24) and blur the component:</p>

<TelerikAutoComplete Data="@ListItems"
                     @bind-Value="@SelectedValue"
                     ValueField="@nameof(ListItem.Text)"
                     DebounceDelay="@AutoCompleteDebounceDelay"
                     OnChange="@OnAutoCompleteChange"
                     OnOpen="@OnAutoCompleteOpen"
                     Width="300px" />

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

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

    private const int AutoCompleteDebounceDelay = 1000;

    private DateTime LastAutoCompleteOnChange { get; set; } = DateTime.Now;

    private void OnAutoCompleteOpen(AutoCompleteOpenEventArgs args)
    {
        if (DateTime.Now - LastAutoCompleteOnChange < new TimeSpan(0, 0, 0, AutoCompleteDebounceDelay * 2))
        {
            //args.IsCancelled = true;
        }
    }

    private void OnAutoCompleteChange(object currentValue)
    {
        LastAutoCompleteOnChange = DateTime.Now;
    }

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

        for (int i = 1; i <= 24; i++)
        {
            ListItems.Add(new ListItem()
            {
                Id = i,
                Text = $"{i}",
                Category = $"Category {i % 6 + 1}"
            });
        }

        base.OnInitialized();
    }

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

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

Declined
Last Updated: 02 Jun 2025 13:25 by ADMIN

Context

The website uses OAuth2 (AzureAd) & https with http version 1 :

"Kestrel": {
"EndpointDefaults": {
"Protocols": "Http1"
}

Glitch

Crash systematically reproduced when user opens website.

Workaround

The issue can be can be manually & individually (per user) fixed by:

  • Executing the instruction: Navigation.NavigateTo($"MicrosoftIdentity/Account/SignOut", true);
  • Closing Edge browser
  • Opening back website
  • Answering OAuth 2 challenge (MicrosoftIdentity/Account/SignIn)

Our client is pushing hard for us to find an automatic solution / patch (which doesn't involve making multiple actions for his users like in my workaround).

1 2 3 4 5 6