Docs/picked from dev (#9578)

* Adding multi project views for Gantt charts (#9572)

* Adding mulit project views for Gantt charts

Adding a menu item for multi project views

* Correction of typo

Co-authored-by: RBernsen <61973994+RBernsen@users.noreply.github.com>

* Changed gif

Replaced gif with newone due to design change of autocompleter

Co-authored-by: Birthe <b.lindenthal@openproject.com>
Co-authored-by: RBernsen <61973994+RBernsen@users.noreply.github.com>

docs/getting-started/my-page/README.md

@@ -93,4 +93,4 @@ You can directly create new time entries by clicking on the day, change the date
 
 Watch the short video to see how to activate the spent time widget, add spent time, edit spent time (e.g. change the date or work packages or change the time booked) and delete spent time.
 
-![my-spent-time-widget](my-spent-time-widget.gif)
+![my-page-time-log](my-page-time-log.gif)

docs/user-guide/gantt-chart/README.md

@@ -21,6 +21,7 @@ The **Gantt chart** in OpenProject displays the work packages in a timeline. You
 | [Understanding the colors and lines in the Gantt chart](#understanding-the-colors-and-lines-in-the-gantt-chart) | What do the clamps, lines and symbols in the Gantt chart mean? |
 | [Gantt chart configuration](#gantt-chart-configuration)      | How to configure the view of your Gantt chart, e.g. add labels? |
 | [Gantt chart views](#gantt-chart-views)                      | How to zoom in and out and activate the Zen mode?            |
+| [Multi project views](#multi-project-views)                  | Create project overarching timelines.                        |
 | [Aggregation by project](#aggregation-by-project)            | How to display an aggregated view of all milestones of multiple projects? |
 
 
@@ -153,7 +154,19 @@ The zen mode gives you more space to focus on the tasks at hand. It's almost lik
 
 
 
-If you want to adjust your work package table and filter, sort or order your work packages to have a better overview in your Gantt chart, please refer to the section [work package table configuration](/../work-packages/work-package-table-configuration/).
+## Multi project views
+
+With the Gantt charts in OpenProject you can create project overarching timelines.
+
+Create multi project timelines  and display all activities, phases and milestones within your project and sub-projects. Also, you can create project overarching timelines by filtering and including respective projects in one joint plan.
+
+To include sub-projects: within the parent project, click on the Filter button and select the subproject(s) you want to have included in your project plan. You can also choose an [aggregation by project](aggregation-by-project).
+
+Use the filter and grouping options as for the [work packages table configuration](../work-packages/work-package-table-configuration/) to customize your timeline. Do not forget to [save your timeline](../work-packages/work-package-table-configuration/#save-work-package-views).
+
+![OpenProject-overarching-project-planning](OpenProject-overarching-project-planning.PNG)
+
+If you not only want to include sub-projects but different independent projects, choose the [global work packages view](../projects/#project-overarching-reports).
 
 ## Aggregation by project