998236: Undo redo and column validation UG documentation

Author: NithyaSivaprakasam

blazor-toc.html

@@ -3160,6 +3160,7 @@
 				</ul>
 			</li>
 			<li> <a href="/blazor/gantt-chart/criticalpath">Critical Path</a> </li>
+			<li> <a href="/blazor/gantt-chart/undo-redo">Undo Redo</a> </li>
 			<li> <a href="/blazor/gantt-chart/tool-bar">Toolbar</a></li>
 			<li> <a href="/blazor/gantt-chart/managing-tasks">Managing Tasks</a>
 				<ul>
@@ -3169,6 +3170,7 @@
 					<li><a href="/blazor/gantt-chart/taskbar-editing">Taskbar Editing</a></li>
 					<li><a href="/blazor/gantt-chart/splitting-and-merging-tasks">Splitting and Merging Tasks</a></li>
 					<li><a href="/blazor/gantt-chart/indent-outdent">Indent and Outdent</a></li>
+					<li><a href="/blazor/gantt-chart/column-validation">Column Validation</a></li>
 					<li><a href="/blazor/gantt-chart/entity-framework">Entity Framework</a></li>
 				</ul>
 			</li>

blazor/gantt-chart/accessibility.md

@@ -182,6 +182,15 @@ The Blazor Gantt Chart component supports comprehensive [keyboard interaction](h
 | <kbd>Tab</kbd> | <kbd>Tab</kbd> | Saves the current cell and moves to the next editable cell in the dialog. |
 | <kbd>Shift</kbd> + <kbd>Tab</kbd> | <kbd>⇧</kbd> + <kbd>Tab</kbd> | Saves the current cell and moves to the previous editable cell in the dialog. |
 
+### Undo Redo
+
+| Windows | Mac | Action |
+|---------|-----|--------|
+| <kbd>Ctrl</kbd> + <kbd>Z</kbd> | <kbd>⌘</kbd> + <kbd>Z</kbd> | Undoes the most recent tracked action. |
+| <kbd>Ctrl</kbd> + <kbd>Y</kbd> | <kbd>⌘</kbd> + <kbd>Y</kbd> | Redoes the most recently undone action. |
+| <kbd>Ctrl</kbd> + <kbd>Shift </kbd> + <kbd>Z</kbd> | <kbd>⌘</kbd>+ <kbd>⇧</kbd> + <kbd>Z</kbd> | Redoes the most recently undone action. |
+| <kbd>Ctrl</kbd> + <kbd>Shift </kbd> + <kbd>Y</kbd> | <kbd>⌘</kbd>+ <kbd>⇧</kbd> + <kbd>Y</kbd> | Undoes the most recent tracked action. |
+
 ## Validate Accessibility Compliance
 
 Accessibility is validated using [axe-core](https://www.nuget.org/packages/Deque.AxeCore.Playwright) with Playwright tests to ensure compliance with WCAG 2.2 and other standards. Evaluate the accessibility of the Blazor Gantt Chart component using the [sample](https://blazor.syncfusion.com/accessibility/gantt-chart) in a new window with accessibility tools.