[CCR-378] Add Search Box documentation to Comparison Pane reference

content/en/docs/refguide/modeling/menus/view-menu/comparison-pane.md

@@ -68,6 +68,23 @@ The task bar contains the following buttons:
 | **Go to** | Opens the selected document and navigates to Level 2 or 3 | Enabled when a document is selected |
 | **Stop comparison** | Closes the comparison and returns to the blank state | Always enabled during an active comparison |
 
+#### Search Box
+
+The task bar contains a search box that filters the document list. The search box is only available at Level 1 and is hidden at Level 2 and Level 3. When no comparison is active, the search box is disabled.
+
+The search matches text against all four columns (status, document name, module name, and details). The match is case-insensitive and applies to any position within the field values. The list updates immediately with each keystroke.
+
+When text is entered, a **Clear** button appears in the search box. Click **Clear** to remove the search text and show all documents again. When no documents match the search text, a message indicates that no results were found.
+
+The following table describes when the search text is retained or reset:
+
+| Scenario | Behavior | Details |
+|----------|----------|---------|
+| Navigating between levels | Retained | The search text persists when navigating to Level 2 or 3 and returning to Level 1 |
+| Hiding and reopening the **Comparison** tab | Retained | The search text persists when the tab is hidden and later reopened in the same session |
+| Starting a new comparison | Reset | The search text is cleared when a new comparison is started |
+| Closing and reopening the app | Reset | The search text is cleared when Studio Pro is closed and reopened |
+
 #### Context Menu
 
 Right-click any cell in the grid to access the **Copy** option, which copies the cell value to your clipboard.