Entries in the System Browser can be sorted in a number of ways. To change the sorting, choose
Tools > Preferences...
or click 
to display the Preferences dialog, and then select
System Browser
in the list on the left side of the dialog. Click on the
General
tab to view the sorting options.
Sorts entries in the main area of the current view (the tree in the tree view and the Files area in the text view) according to the symbol name.
Sorts entries in the main area according to their package.
Leave entries in the main area unsorted. This is the default setting.