Thanks sobe !
I got the radar scope appearing in the 2nd screen, but now my Ikarus instruments disappeared.
I'll explain better:
I have a 2nd screen (a tablet with 1280x800) where I want to display the radar and 4 other instruments (VVI, etc.)
Before, solving the radar issue, the instruments were working, but I got an empty frame for the radar.
Now, with the radar working (through the creation of a specific viewport redirected to the tablet), all the instruments get overwritten, despite the radar coordinates not intruding into the instruments.
Any ideas ?