Yoh, well. Since FSDT sells sceneries with an addonmanager (which always has been doubtful why) and makes it some kind of incompatible to previous released software
The current version of the Addon Manager is fully compatible with the QW757. See the video below.
I know and you know too, this discussion is not new and will never stop if until these situations are treated the right way.
The situation IS being treated in the right way, which is offering the suggestion that works: never install the QW757 *after* having installed something using the latest FSDT installer. If you do it, reinstall either the Stand-Alone Addon Manager or any other FSDT installer, will fix everything.
Fact is, the QW757 will not load in the first place
It does. See the video below.
For me it doesn‘t make a difference in which order you install everthing.
The installation order makes all the difference. If you install the QW757 last, it's 100% sure it won't work. If you install something from FSDT last, it's 100% sure it will work.
Simple, but that is a bug produced by FSDT. It‘s not about the old installers, no, it‘s about the new installers!
It's no "bug" produced by FSDT. It's ALL about the old installer because they were using a different file structure, but the new installers WILL fix this, if they are run last.
Here's a video I just made, showing the QW757 fully working in both FSX:SE and P3D 3.4, showing gauges working normally, at the first startup of the sim, without having to load the airplane twice.