P3D v4 TmfViewer

I have installed both Prepar3D v4 SDK and Flight Simulator X SDK \ SDK SP2 and there is a strange problem with the association of BGL (terrain mesh) files.

When I click on a bgl it is automatically associated with the tmfviewer of FSX SDK 10.0.61472.0. Then I wanted to change so as to associate the opening of the file to the tmfviewer of P3D (

I can not change this setting, the P3D tmfviewer can not be associated.

Do you have any suggestions? Can you check to see if you have the same problem?

If your are on Windows 7 or Windows 10, click on the BGL, and browse to "open with" select your good version and click on "always ...".
I am French dev. so my Windows is in French language so I cannot be sure of the item in your GUI.
Thnks for your time. I also did this .... but I can set the tmfviewer of P3D. I think of a bug in the related exe file. then you try if your system works?
Thanks to an intuition of Dick "rhumbaflappy" has hit the mark!

Of course this is a limitation of W7. Having both installed the version of FSX and the version of P3D, keep in association the first tmfviewer (FSX). Renaming one of the two indifferently, in this case I renamed the tmfviewer (P3D) in tmfviewer_P3Dv43, you can also bet on the tmfviewer of P3D.

As you can see in the attached photo now in Open with ... I can choose the version. The displayed name and the signature are associated by W7 which read them in the properties of the relative tmfviewer file.

Yours sincerely