🚀 go-pugleaf

I am using a disk cache program, that I found in comp.sources.atari.st, for 
caching floppy disk sectors.
I detected a problem when switching directories within a window
at the desktop. Each time the directory is changed, a media change
indication occurs and the cache is reset (the reset is desired as normal 
action after a real media change). However, there was no actual media change,
nevertheless the BIOS.mediach propagates a real media change (not only 
a warning: media may have been changed), and a BIOS.rwabs returns -14 (media
changed). For the cache program there is no possibility to distinguish 
between this pseudo media change indication and a real media change.

Such pseudo media change indications do not occur when directories are
changed within a command shell or within a program.

What extra operations is the desktop doing above the normal GEMDOS operations
for directory changes ?
What is the reason for this behaviour of the desktop?
How can I recognize a real media change ? 

Thanks for any help!