Sometimes it's easy to have only two or more Projects visible in your Dashboard or Calendar. Take the following steps to get your settings right.
Dashboard
Go to Dashboard.
Then, go to the Select Projects-icon on the right.
From here you can select and de-select the Projects you want to be shown and which not.
Calendar
Go to Calendar.
Click on Manage in the top left.
From here you can select and de-select the Projects you want to be shown and which not.
Note: when you open an event and leave the Calendar, the settings will be on default again.