Okay, so I have a nearly identical "black box" on mine but not 100% identical. Still, the description fits.
I'm running Debian GNU/Linux, Etch/Lenny with a hint of Sid, custom-compiled SEVERAL versions of FlightGear, SimGear, OpenSceneGraph. I can say that OpenSceneGraph 2.7.8 with FlightGear and SimGear both at 1.99.5-rc2 have this problem, so an upgrade to OSG.latest is not the fix in this case. Personally, I spent 11 hours this week upgrading from an ancient version 0.9 installed from Debian packages to 1.9.0 installed from source (and all the prereq's and must-have-latest-cvs-version-of-everythings that go with it) and then several hours more trying to compile the absolute latest available code of OSG, SG, and FG and no matter what I've done, I've got graphical bugs.
In my case, the black box starts at the ground and will touch ground until I'm at least 300 feet in the air. It's right edge is always dead center of my screen, and runs from bottom of screen (or ground, whichever is higher) to about 2/3 of the height of the screen (someone else mentioned 70% -- this is about right). View angle does not affect it, aircraft position does not affect it, view source (cockpit, tower, chase) does not affect it. It's always there.
http://gallery.dennettesdesigns.com/mai ... &g2_page=7
http://gallery.dennettesdesigns.com/mai ... &g2_page=9
It also is not affected by the aircraft, nor location. Above was at KSFO, San Fran, below was at KNIP, Jacksonville FL.
http://gallery.dennettesdesigns.com/mai ... g2_page=10
[edit: Turns out (see below) that some aircraft ARE affected and some ARE NOT.]
Feel free to browse the above, but know that I'm on a residential cable line and I don't know how Comcast feels about serving on port 80. If anyone else can host my screencaps above, feel free to grab them and post a new location. Thanks!
Also, I'm running on an old nVidia GeForce2 Ti card with IIRC only 64 MB of vidram. I saw someone else had an ATI, so I believe it's not a card or driver issue. Since it's present on Linux and Windows, I'll say it's not an OS issue.
The last post here says there's info shown in the black box, but the only thing I ever see displayed on mine is my HUD. However, I too have an AMD Athlon64 3000+ (2.0 GHz chip) though I wonder how many others have it.
Finally, when doing ./configure in the Linux compile, I do notice it complaining (one of the packages) that I don't have wxWidgets. Could this be a part of the problem?
Any further info much appreciated. Now that I've found this forum, I plan to keep an eye on it....