<TelerikContextMenu Data="@MenuItems" Selector="#menu-target"
                    Class="menu-on-top" />

<style>
    .menu-on-top,
    .k-animation-container:has(.menu-on-top) {
        z-index: 11000 !important;
    }
</style>

<TelerikWindow Width="240px" Height="160px"
               Top="100px" Left="100px"
               Visible="true" Modal="true">
    <WindowTitle>Window</WindowTitle>
    <WindowContent>
        <div style="height:60px;border: 1px solid;"
             id="menu-target">Right-click me</div>
    </WindowContent>
</TelerikWindow>

@code {
    List<ContextMenuItem> MenuItems { get; set; } = new List<ContextMenuItem>();

    protected override void OnInitialized()
    {
        for (int i = 1; i <= 7; i++)
        {
            MenuItems.Add(new ContextMenuItem() { Text = $"Menu item {i}" });
        }

        base.OnInitialized();
    }

    public class ContextMenuItem
    {
        public string Text { get; set; } = string.Empty;
    }
}

<TelerikWindow Width="80%"
                Height="auto"
                Top="404px"
                State="WindowState.Minimized"
                Left="200px"                        
                Class="myClass"
                Visible="true"
><WindowTitle>My Title</WindowTitle><WindowActions><WindowAction Name="Minimize"></WindowAction></WindowActions><WindowContent><h1>My Content</h1></WindowContent></TelerikWindow>
 
Window starts out minimized, with proper width, height, top and left.
Clicking maximize button clears the top and left property, and resets position every time you open/close.
Click/dragging to move the window will reapply top/left property, and then maximize/minimize works properly.
 
If you change the state to to WindowState.Maximized, it has the correct top/left property, but resets the width/height properties.
Window is not draggable.
 
Not setting the State at all is the only way to have proper behavior.
    
    
        
    
    
        
    

<TelerikWindow Visible="true" Class="workaround-for-touch-drag">
    <WindowTitle>the title</WindowTitle>
    <WindowContent>the content</WindowContent>
</TelerikWindow>

<style>
    .workaround-for-touch-drag {
        touch-action: none;
    }
</style>

<div style="height:400px;"></div>
<TelerikButton Icon="window" OnClick=@(()=> WindowVisible = true)>Open Modal</TelerikButton>
<div style="height:400px;"></div>

<TelerikWindow Class="demo-window" Width="500px" Height="300px" Centered="true" @bind-Visible=@WindowVisible Modal="true">
    <WindowTitle>
        <strong>Modal Window</strong>
    </WindowTitle>
    <WindowActions>
        <WindowAction Name="Close" />
    </WindowActions>
    <WindowContent>
        <p>Click the close button to dismiss this modal dialog.</p>
    </WindowContent>
</TelerikWindow>

@code { public bool WindowVisible { get; set; } }

<style type="text/css">
    .demo-window {
        z-index: 44444;
    }
</style>

<WindowAction Name="Maximize" Hidden="true"></WindowAction>

See this REPL for an example:
https://blazorrepl.telerik.com/wPbGYMvi23qjUo1c41

<style>
    .k-animation-container {
        z-index: 15000;
    }
</style>


<TelerikGrid Data=@MyData EditMode="@GridEditMode.Popup" Pageable="true" Height="300px" OnUpdate="@UpdateHandler">
    <GridColumns>
        <GridColumn Field=@nameof(SampleData.ID) Editable="false" Title="ID" />
        <GridColumn Field=@nameof(SampleData.Name) Title="Name" />
        <GridColumn Field=@nameof(SampleData.Roles) Title="Position">
            <Template>
                @{
                    var item = context as SampleData;

                    @if (item.Roles.Any())
                    {
                        foreach (var role in item.Roles)
                        {
                            <span>@role</span>
                        }
                    }
                }
            </Template>
            <EditorTemplate>
                @{
                    CurrentlyEditedEmployee = context as SampleData;
                    <TelerikMultiSelect @bind-Value="@selectedValues" Data="@CurrentlyEditedEmployee.Roles"></TelerikMultiSelect>
                }
            </EditorTemplate>
        </GridColumn>
        <GridCommandColumn>
            <GridCommandButton Command="Save" Icon="save" ShowInEdit="true">Update</GridCommandButton>
            <GridCommandButton Command="Edit" Icon="edit">Edit</GridCommandButton>
        </GridCommandColumn>
    </GridColumns>
</TelerikGrid>

@code {
    List<SampleData> MyData { get; set; }
    List<string> Roles { get; set; }
    SampleData CurrentlyEditedEmployee { get; set; }

    private List<string> selectedValues { get; set; }

    public async Task UpdateHandler(GridCommandEventArgs args)
    {
        SampleData item = (SampleData)args.Item;

        // perform actual data source operations here through your service
        await MyService.Update(item);

        // update the local view-model data with the service data
        await GetGridData();
    }

    //in a real case, keep the models in dedicated locations, this is just an easy to copy and see example
    public class SampleData
    {
        public int ID { get; set; }
        public string Name { get; set; }
        public List<string> Roles { get; set; } = new List<string>() { "Test" };
    }

    async Task GetGridData()
    {
        MyData = await MyService.Read();
        Roles = await MyService.GetRoles();
    }

    protected override async Task OnInitializedAsync()
    {
        await GetGridData();
    }

    // the following static class mimics an actual data service that handles the actual data source
    // replace it with your actual service through the DI, this only mimics how the API can look like and works for this standalone page
    public static class MyService
    {
        private static List<SampleData> _data { get; set; } = new List<SampleData>();
        private static List<string> Roles = new List<string> { "Manager", "Employee", "Contractor" };

        public static async Task<List<SampleData>> Read()
        {
            if (_data.Count < 1)
            {
                for (int i = 1; i < 50; i++)
                {
                    _data.Add(new SampleData()
                    {
                        ID = i,
                        Name = "Name " + i.ToString()
                    });
                }
            }

            return await Task.FromResult(_data);
        }

        public static async Task<List<string>> GetRoles()
        {
            return await Task.FromResult(Roles);
        }

        public static async Task Update(SampleData itemToUpdate)
        {
            var index = _data.FindIndex(i => i.ID == itemToUpdate.ID);
            if (index != -1)
            {
                _data[index] = itemToUpdate;
            }
        }
    }
}