Added new kb article radgrid-white-box-dragging-columns (#701)

Co-authored-by: KB Bot <[email protected]>

Author: github-actions[bot]

knowledge-base/radgrid-white-box-dragging-columns.md

@@ -0,0 +1,74 @@
+---
+title: Dragging a Column in RadGrid Displays a Large White Box
+description: Resolving the issue where dragging a column in RadGrid with virtual scroll enabled displays a large white box instead of matching the column width.
+type: troubleshooting
+page_title: Large White Box Appears While Dragging Columns in RadGrid
+meta_title: Large White Box Appears While Dragging Columns in RadGrid
+slug: radgrid-white-box-dragging-columns
+tags: radgrid, asp.net ajax, css, column-reordering, virtual-scroll, debugger, styles
+res_type: kb
+ticketid: 1691575
+---
+
+## Environment
+
+<table>
+<tbody>
+<tr>
+<td>Product</td>
+<td>RadGrid for ASP.NET AJAX</td>
+</tr>
+<tr>
+<td>Version</td>
+<td>2022.2.622</td>
+</tr>
+</tbody>
+</table>
+
+## Description
+
+When dragging a column to a new position in a [RadGrid](https://docs.telerik.com/devtools/aspnet-ajax/controls/grid/overview) with virtual scroll paging enabled, a large white box appears instead of matching the width of the column. This behavior is caused by CSS rules overriding the dragger's styling, making it stretch across the screen.
+
+## Cause
+
+The issue occurs because RadGrid generates a floating dragger element styled with dimensions matching the column width. If global CSS rules applied to `table`, `tr`, or `td` elements on the page override these styles (e.g., `width: 100%` or `display: block`), the dragger element expands beyond the intended size.
+
+## Solution
+
+To achieve the correct behavior, apply CSS overrides to constrain the dragger's width. Follow these steps:
+
+1. Open the browser's Developer Tools by pressing F12.
+2. Use the following script to pause execution while dragging a column:
+   ```javascript
+   setTimeout(function(){ debugger; }, 3000);
+   ```
+3. Drag a column header and inspect the `<div>` element with classes like `rgHeader rgHeaderOver RadGrid RadGrid_Silk` and its `<table>` child.
+4. Inspect your site stylesheets for global CSS rules applied to `table`, `tr`, or `td` elements, and ensure they do not override RadGrid's styling. Applying the above CSS constraints resolves the issue.
+5. Alternatively apply the following CSS rules to limit the dragger's width:
+
+   Limit the dragger width to its content:
+   ```css
+   div.rgHeaderOver table {
+       width: auto !important;
+       table-layout: auto !important;
+   }
+   ```
+
+   Force the dragger to match the column width:
+   ```css
+   div.rgHeaderOver {
+       width: auto !important;
+       max-width: 200px; /* Adjust to the column width */
+   }
+
+   div.rgHeaderOver table {
+       width: auto !important;
+   }
+   ```
+
+
+## See Also
+
+- [RadGrid Documentation](https://docs.telerik.com/devtools/aspnet-ajax/controls/grid/overview)
+- [Troubleshooting CSS Issues - Part 1](https://www.telerik.com/blogs/improve-your-debugging-skills-with-chrome-devtools)
+- [Troubleshooting CSS Issues - Part 2](https://www.telerik.com/blogs/improve-your-debugging-skills-with-chrome-devtools-(part-2))