How can I turn OFF auto-raise?

[LenW]

How can I get my window manager to IGNORE an application's request
to raise its window to the top?
At least that's my best guess as to what is going on.
I am looking at getting a commercial application (Harmony Assistant from
Myriad Software). I appreciate their efforts to provide a Linux version,
but it behaves in a way I have never seen before. It seems to operate
very quickly, which I fear they have accomplished by bypassing standard APIs.

In any case, the app's window automatically rises to the top immediately
when the mouse cursor enters its window, despite my Windows Preference
behavior setting which DISables the option that would
"Raise the selected window".

How can I keep the application from doing this?
(I have tried to contact the vendor to no avail.)

I am running Linux Mint 19.1 MATE with the default window manager (Marco).