Unsolved Implementing bluetooth - general questions - part 2 - all about using "blueZ" library - in Linux

[AnneRanch]

This library is a cornerstone of many bluetooth applications.
Sometime this is not advertised and one has to find out the hard way.
However, reading in-between the lines - Linux OS includes "blueZ" library as a standard package.

In theory I could;d use "system" or library .

( I am currently using ":system" calls to bypass Qt issue - posted a bug)

On my flavour of Linux - Ubuntu I have "blueman_applet" AKA
"GTK based Bluetooth manager" . It is optioned as "visible on menu bar". It has been painful source of intermittent problems in past, but it is relatively stable now. It is also advertised as "Bluetooth Manager".

This "Bluetooth Manager" "runs in background" .
By that I mean - when I run my bluetooth application and for example change " bluetooth visibility " I can see such change reflected on "Bluetooth Manager".

My question
Is is correct to state that MY application is changing system setting ?

Secondary question
After invoking bluetooth paring in MY application I get what appears dialogs / progress "widgets" clearly coming ( label as such ) FROM "Bluetooth Manager" .

I am not sure HOW is this happening. I have not run my app in debug mode, not yet.

Cheers