As students register for spring courses, WISE sites are being automatically created. This process may move your current courses lower in your course hierarchy and suddenly remove current courses from your tab bar. Don't panic; those courses are still available by clicking on the arrow in the "-more-" box to the right of your list of tabs.
To rearrange the order of your sites, click on your "My Workspace" tab and then select "Preferences" from the Tools list. This will put you on the "Customize Tabs" page. Click on the name of a site and then click the up or down arrows to the right of the list to move the site up or down in the hierarchy (the first 4 items will be displayed as tabs). If you don't want to see a site at all, click on the name of the site and then click the left-pointing arrow to move the site to the "do not show" list. This will not remove you from the site; you can always move it back to the "show" list or access it using the "Membership" tool in your My Workspace site.