[DOCS] Adds dashboard troubleshooting (#111570)

* [DOCS] Adds dashboard troubleshooting

* Adds asciidoc file to dashboard

* Adds Timelion app image

* Update docs/user/dashboard/dashboard-troubleshooting.asciidoc

Co-authored-by: gchaps <33642766+gchaps@users.noreply.github.com>

* Review comments

Co-authored-by: gchaps <33642766+gchaps@users.noreply.github.com>

docs/user/dashboard/dashboard-troubleshooting.asciidoc

@@ -0,0 +1,69 @@
+[[dashboard-troubleshooting]]
+== Dashboard and visualizations troubleshooting
+++++
+<titleabbrev>Troubleshooting</titleabbrev>
+++++
+
+Find solutions to common dashboard and visualization issues.
+
+[float]
+[[defer-loading-panels-below-the-fold]]
+=== Improve dashboard loading time
+
+To improve the dashboard loading time, enable *Defer loading panels below the fold* *Lab*, which loads dashboard panels as they become visible on the dashboard.
+
+. In the toolbar, click *Labs*.
++
+To enable *Labs*, contact your administrator, or configure the <<presentation-labs,Advanced Settings>>. 
+
+. To specify how you want to enable the lab, use the following actions:
+
+* *{kib}* &mdash; Enables the lab in {kib}.
+
+* *Browser* &mdash; Enables the lab for your browser, and persists after you close the browser.
+
+* *Session* &mdash; Enables the lab for this browser session, then resets after you close the browser.
+
+. Click *Close*.
+
+[float]
+[[migrate-timelion-app-worksheets]]
+=== Migrate Timelion app worksheets
+
+deprecated::[The *Timelion* app is deprecated in 7.0.0, and will be removed in 7.16.0. To prepare for the removal of *Timelion* app, you must migrate *Timelion* app worksheets to a dashboard.
+
+. Open the main menu, then click *Dashboard*.
+
+. On the *Dashboards* page, click *Create dashboard*.
+
+. For each *Timelion* app worksheet, create a visualization with the *Timelion* editor.
+
+.. On the dashboard, click *All types > Aggregation based*, then select *Timelion*.
+
+.. In your browser, open a new tab, the open the *Timelion* app.
+
+.. Select the chart you want to copy, then copy the chart expression.
++
+[role="screenshot"]
+image::images/timelion-copy-expression.png[Timelion app chart]
+
+.. Go to the *Timelion* editor, paste the chart expression in the *Timelion expression* field, then click *Update*.
++
+[role="screenshot"]
+image::images/timelion-vis-paste-expression.png[Timelion advanced editor UI]
+
+. Save the visualization.
+
+.. In the toolbar, click *Save to library*.
+
+.. Enter the *Title* and add any applicable <<managing-tags,*Tags*>>.
+
+.. Make sure that *Add to Dashboard after saving* is selected.
+
+.. Click *Save and return*.
++
+The Timelion visualization panel appears on the dashboard.
++
+[role="screenshot"]
+image::user/dashboard/images/timelion-dashboard.png[Final dashboard with saved Timelion app worksheet]
+

docs/user/dashboard/dashboard.asciidoc

@@ -293,26 +293,6 @@ Download panel data in a CSV file. When you download visualization panels with m
 
 * *Unformatted* — Best used for computer use.
 
-[float]
-[[defer-loading-panels-below-the-fold]]
-== Improve dashboard loading time
-
-To improve the dashboard loading time, enable the *Defer loading panels below the fold* *Lab*, which loads the dashboard panels as they become visible on the dashboard.
-
-. In the toolbar, click *Labs*.
-+
-To enable *Labs*, contact your administrator, or configure the <<advanced-options,Advanced Settings>>. 
-
-. To specify how you want to enable the lab, use the following actions:
-
-* *{kib}* &mdash; Enables the lab in {kib}.
-
-* *Browser* &mdash; Enables the lab for your browser, and persists after you close the browser.
-
-* *Session* &mdash; Enables the lab for this browser session, then resets after you close the browser.
-
-. Click *Close*.
-
 [float]
 [[share-the-dashboard]]
 == Share dashboards
@@ -333,3 +313,5 @@ include::lens-advanced.asciidoc[]
 include::create-panels-with-editors.asciidoc[]
 
 include::make-dashboards-interactive.asciidoc[]
+
+include::dashboard-troubleshooting.asciidoc[]

docs/user/dashboard/timelion.asciidoc

@@ -13,6 +13,8 @@ The syntax enables some features that classical point series charts don't offer,
 [role="screenshot"]
 image:dashboard/images/timelion.png[Timelion]
 
+deprecated::[7.0.0,"*Timelion* is still supported. The *Timelion app* is deprecated in 7.0, replaced by dashboard features. In 7.16 and later, the *Timelion app* is removed from {kib}. To prepare for the removal of *Timelion app*, you must migrate *Timelion app* worksheets to a dashboard. For information on how to migrate *Timelion app* worksheets, refer to <<migrate-timelion-app-worksheets,Migrate Timelion app worksheets>>."]
+
 [float]
 ==== Timelion expressions