Discover tabs (#3446)

This PR:

- Adds a section about using tabs in Discover and how to manage these
tabs
- Edits the Save Discover session section to add the notion of tabs
being saved as part of the Discover session
- Adds a note about recommended fields (unrelated to tabs but noticed
this on the way)

Closes: #3145

---------

Co-authored-by: Benjamin Ironside Goldstein <[email protected]>
Co-authored-by: Davis McPhee <[email protected]>

Author: 3 people

explore-analyze/discover/discover-get-started.md

@@ -94,6 +94,8 @@ You can later filter the data that shows in the chart and in the table by specif
    You can combine multiple keywords or characters. For example, `geo dest` finds `geo.dest` and `geo.src.dest`.
    ::::
 
+   {applies_to}`stack: ga 9.2` For some searches, Discover suggests recommended fields to explore. These suggestions are based on the data you query and are managed by Elastic.
+
 2. Select a field to view its most frequent values.
   **Discover** shows the top 10 values and the number of records used to calculate those values.
 
@@ -303,6 +305,39 @@ Note that in ES|QL mode, the **Documents** tab is named **Results**.
 
 Learn more about how to use ES|QL queries in [Using ES|QL](try-esql.md).
 
+### Run multiple explorations with tabs
+```{applies_to}
+stack: preview 9.2
+serverless: preview
+```
+**Discover** supports multiple tabs to help you explore different aspects of your data simultaneously. Each tab maintains its own independent state, including the query ({{esql}} or classic mode), time range, filters, selected data source, columns and sort order you defined, and the active [context-aware experience](#context-aware-discover).
+
+This allows you to pivot quickly between different explorations without losing your place. For example:
+
+* **Compare time periods:** Open multiple tabs with the same query but different time ranges
+* **Test query variations:** Duplicate a tab to experiment with different {{esql}} queries or filters
+* **Switch contexts:** Keep separate tabs for logs, metrics, and traces explorations
+* **Test a hypothesis:** Switch between different data sources or field combinations
+
+#### Manage Discover tabs
+
+You can open new tabs or duplicate existing ones to compare different queries:
+- To start a fresh exploration in a new tab, select the {icon}`plus` icon next to the existing tabs.
+- To test variations of your current query in a new tab, hover over a tab and select the {icon}`boxes_vertical` **Actions** icon, then select **Duplicate**.
+
+To manage and organize your tabs, you can: 
+- Rename them: Double-click its label or hover over a tab and select the {icon}`boxes_vertical` **Actions** icon, then select **Rename**.
+- Reorder them: Drag and drop a tab to move it.
+- Close them: Hover over a tab and select the {icon}`cross` icon.
+- Close several tabs at once: When you hover over a tab and select the {icon}`boxes_vertical` **Actions** icon, options let you **Close other tabs** to keep only the active tab open or **Close tabs to the right** to only keep your first tabs and discard any subsequent tabs.
+
+  :::{tip}
+  If you want to discard all open tabs, you can also start a {icon}`plus` **New session** from the toolbar. When you use this option, any unsaved changes to your current session are lost. 
+  :::
+- Reopen recently closed tabs: If you close a tab by mistake, you can retrieve it by selecting the {icon}`boxes_vertical` **Tabs bar menu** icon located at the end of the tab bar.
+
+To keep all of your tabs for later, you can [Save your Discover session](#save-discover-search). All currently open tabs are saved within the session and will be there when you open it again.
+
 ### Inspect your Discover queries
 
 :::{include} ../_snippets/inspect-request.md
@@ -319,7 +354,7 @@ You can send your long-running KQL or {{esql}} queries to the background from **
 
 ### Save your Discover session for later use [save-discover-search]
 
-Save your Discover session so you can use it later, generate a CSV report, or use it to create visualizations, dashboards, and Canvas workpads. Saving a Discover session saves the query text, filters, and current view of **Discover**, including the columns selected in the document table, the sort order, and the {{data-source}}.
+Save your Discover session so you can use it later, generate a CSV report, or use it to create visualizations, dashboards, and Canvas workpads. Saving a Discover session saves all open tabs, along with their query text, filters, and current view of **Discover**, including the columns selected in the document table, the sort order, and the {{data-source}}.
 
 1. In the application menu bar, click **Save**.
 2. Give your session a title and a description.