It is sometimes convenient to hide tabs that are not being used, or to re-order the tabs so that the most often used are displayed together.  To rearrange or hide tabs, launch the User Preferences panel from the Edit menu.  Under "General User Preferences" there is line entitled "Tab Order".  On that line, any of the available tabs can be selected by name, and the corresponding (left-to-right) ordering index is displayed.  An ordering of 0 indicates that tab is not displayed.  The ordering index can be edited as desired.  Click the "Show" or "Hide" button to cause the indicated panel to be shown or hidden.