Admin plannig view

To select a project, just select it in the "project selector" on top left side of the screen.

The message you get is a limitation that can be configured in "global configuration" screen as "max projects to display".
You get this message when you try to display more than this limit in the gantt.

This limitation exists to avoid blocking your browser with a gantt too complex to display.
Most performance constraints have been removed since V3.4, so you can easily increase the limit up to 100 or even more (depneding on your workstation capacity).