kb(grid): Add KB for focusable elements inside a navigable Grid template

knowledge-base/grid-cannot-open-dropdown-in-navigable-grid.md

@@ -0,0 +1,127 @@
+---
+title: Cannot Open a DropDownList inside a Navigable Grid
+description: Learn how to troubleshoot the inability to focus or open a Button, DropDownList, ComboBox, or other components inside a navigable Telerik Grid for Blazor.
+type: troubleshooting
+page_title: Cannot Open a DropDownList inside a Navigable Grid
+slug: grid-kb-cannot-open-dropdown-in-navigable-grid
+tags: telerik, blazor, grid, treelist
+ticketid: 1623773
+res_type: kb
+---
+
+## Environment
+
+<table>
+    <tbody>
+        <tr>
+            <td>Product</td>
+            <td>
+                Grid for Blazor, <br />
+                TreeList for Blazor
+            </td>
+        </tr>
+    </tbody>
+</table>
+
+## Description
+
+Dropdown components do not open inside a Grid column `<Template>` when the Grid has [`Navigable="true"`](https://demos.telerik.com/blazor-ui/grid/keyboard-navigation).
+
+## Cause
+
+When the Grid keyboard navigation is enabled, the table cells automatically gain focus when a cell is clicked. If the cell contains a focusable element, this element may lose focus unexpectedly on click.
+
+## Solution
+
+Normally, editor components belong to [`<EditorTemplate>`]({%slug grid-templates-editor%})s, but this article assumes that editor templates are not an option. Thus, other possible options include:
+
+* If data operations like sorting and filtering are not necessary for the affected columns, place buttons or dropdown components like ComboBox or DropDownList inside a [Grid Command Column]({%slug components/grid/columns/command%}) instead. Grid command columns do not gain focus automatically when a nested focusable element is clicked.
+* If data operations for the affected columns are required, then use a container with `@onclick:stopPropagation` inside the `<GridColumn>` template. This will prevent the Grid from knowing about the clicks, so the data cell will not gain focus automatically.
+
+>caption Using dropdowns, buttons and other focusable elements inside a navigable Grid
+
+```RAZOR
+<TelerikGrid Data="@GridData" Navigable="true">
+    <GridColumns>
+        <GridColumn Field="@nameof(Product.Name)" Title="Cells will steal focus on click" HeaderClass="warning">
+            <Template>
+                @{ var dataItem = (Product)context; }
+                <span class="template-span">
+                    <TelerikButton OnClick="@( () => OnButtonClick(dataItem.Id) )">@dataItem.Name</TelerikButton>
+                    <TelerikDropDownList Data="@DropDownListData" @bind-Value="@dataItem.Active" />
+                </span>
+            </Template>
+        </GridColumn>
+        <GridColumn Field="@nameof(Product.Name)" Title="Template with stopPropagation" HeaderClass="success">
+            <Template>
+                @{ var dataItem = (Product)context; }
+                <span @onclick:stopPropagation class="template-span">
+                    <TelerikButton OnClick="@( () => OnButtonClick(dataItem.Id) )">@dataItem.Name</TelerikButton>
+                    <TelerikDropDownList Data="@DropDownListData" @bind-Value="@dataItem.Active" />
+                </span>
+            </Template>
+        </GridColumn>
+        <GridCommandColumn Title="Command Column" HeaderClass="success">
+            @{ var dataItem = (Product)context; }
+            <span class="template-span">
+                <TelerikButton OnClick="@( () => OnButtonClick(dataItem.Id) )">@dataItem.Name</TelerikButton>
+                <TelerikDropDownList Data="@DropDownListData" @bind-Value="@dataItem.Active" />
+            </span>
+        </GridCommandColumn>
+    </GridColumns>
+</TelerikGrid>
+
+<style>
+    .template-span {
+        display: flex;
+        gap: 1em;
+        padding: .3em;
+    }
+
+    .warning {
+        background-color: var(--kendo-color-warning);
+    }
+
+    .success {
+        background-color: var(--kendo-color-success);
+        color: var(--kendo-color-on-success);
+    }
+</style>
+
+@code {
+    List<Product> GridData { get; set; } = new();
+
+    List<bool> DropDownListData { get; set; } = new List<bool>() { true, false };
+
+    private void OnButtonClick(int id)
+    {
+        Console.WriteLine($"Button click on data item {id}");
+    }
+
+    protected override void OnInitialized()
+    {
+        for (int i = 1; i <= 3; i++)
+        {
+            GridData.Add(new Product()
+            {
+                Id = i,
+                Name = $"Name {i}",
+                Active = i % 3 == 0
+            });
+        }
+    }
+
+    public class Product
+    {
+        public int Id { get; set; }
+        public string Name { get; set; } = string.Empty;
+        public bool Active { get; set; }
+    }
+}
+```
+
+## See Also
+
+* [Grid Keyboard Navigation Demo](https://demos.telerik.com/blazor-ui/grid/keyboard-navigation)
+* [Grid Column Template]({%slug grid-templates-column%})
+* [Grid Command Column]({%slug components/grid/columns/command%})