I've posted a detailed description at https://stackoverflow.com/questions/65161907/attempting-to-start-apache-app-xampp-panel-never-shows-running-though-it-is
But the gist is that everything seems to work okay as with previous versions of xampp. Using xampp-control.exe I can start and stop MySQL as always. But when I start Apache, the Apache module name never gets highlighted or the PID and port displayed, or the Start button changed to Stop. Yet clicking Netstat shows httpd.exe listening on 0.0.0.0 port 80, my vhosts on localhost display fine in my browser, and the apache error log looks normal. The only way I've found to stop apache is to use netstat to find the PID listening on port 80, and then use process explorer to kill that PID.
On a slightly different note, just now I tried running apache_stop.bat, and nothing happened (no output and it's still running). Looking at the source of the script, I see the guts of it is:
call "@@BITROCK_INSTALLDIR@@\killprocess.bat" "httpd.exe"
I have no idea about @@BITROCK_INSTALLER@@ but I can see that there is no file named "killprocess.bat" anywhere below the xampp installation tree...
Thanks for any help!