If you're part of a space, but it's not listed in your left hand taskbar, don't worry, you can add it back!
Adding a space back to your list of Spaces
First, click on the plus sign (+) next to Spaces.
Next, click on the "Browse Spaces" button.
Now you can search for your space. Either type the space name in the field, or scroll up and down until you find it. Click on the space to open it and restore it to your list of spaces.
How to remove a space from your space list
To remove a space from your space list, mouse-over the space name in your left-hand task bar then click on the X next to the space name. A confirmation dialogue will ask you to confirm the removal - click yes to remove the space from your list.
To learn how to change the privacy setting of a space, click here.