If you have opened any symbols files by selecting Load Debug Symbols... from the File menu and using the resulting browse dialog, you can reopen any of the few most recently opened more easily by selecting Recent Symbols.

A submenu lists the files you have already opened and you can click on any filename in the list to open that file again.

To change the number of files that can appear in the list, select Options ? Configure Interface ? General, set a new value for Recent Symbols List size, and click OK.