Pick Sort Project Tabs Alphanumerically from the Go menu to sort the tabs of all projects alphanumerically by their names. Alphanumeric order is like alphabetic order. But if your file names contain numbers, those numbers are interpreted as a whole. So Project2.epp comes before Project10.epp because 2 comes before 10. This sort order is also known as “natural sort”. Windows Explorer uses the same method for sorting files and folders by their names.
Note that the project tabs are sorted only at the moment you click on Sort Project Tabs Alphanumerically. If you open more projects, the alphanumerical order is not maintained. Tabs for newly opened projects are always placed to the immediate right-hand side of the tab that was active when you opened the additional files.
You can also rearrange the tabs in any order you want by dragging them with the mouse. To drag a tab, click on it, hold the mouse button down, and move the mouse to the left or right. The tab will follow the mouse pointer until you release the mouse button. If you drag the tab to the left edge of the leftmost tab, and there are more tabs, presently invisible, to the left of that tab, then all the tabs will scroll to the right, allowing you to move the tab you are dragging further to the left. Similarly, you can drag the tab to the right edge of the rightmost tab to make the tabs scroll to the left.
As explained for Go|Sort File Tabs Alphanumerically, Windows Explorer can be set to sort alphabetically rather than alphanumerically. If you did this then Go|Sort Project Tabs Alphanumerically also uses alphabetic sort. The menu item’s label does not change to reflect this.