To
rearrange the order of tabs in a region, you must have at least one
of the following privileges:
Rearranging the order of tabs in a region
You can change the order in which tabs are displayed in a region.
To
rearrange the order of tabs in a region, you must have at least one
of the following privileges:
Manage All privileges on the page group to which the page belongs
Manage privileges on the page
Manage global privileges on All Pages
If you have full customization privileges on a page, you can also rearrange the order of tabs when you customize the page. However, any changes you make to the order of tabs will be visible only to you.
To rearrange the order of tabs in a region:
Go to the page with which you want to work.
Switch to Edit mode.
In the region that contains the tabs you want to rearrange, click 
.
In the Arrange Tabs list, select a tab and use the arrows to reorder it in relation to the other tabs in the list.
Repeat step 4 for as many of the tabs as you need to rearrange.
When you are done, click OK.