The Floating Panel does not allow classifying the applications in any alphabetical order.
However, what you can do is make a backup copy of the file ‘AppControl.ini’ located here:
C: \ program files (x86 \ rdplus \ userdesktop \ files \ AppControl.ini
Open AppControl.ini with a Notepad and edit it: change the order of the applications from [App6].
The applications assigned in the Floating panel will then have the desired display order.