MS was helping me out with my issue of not being able to use an ImageBrush and then render DVD playback. ends up it worked for them on a 128 MB Radeon 9800. i've got a much lamer GeForce FX Go5200 AGP 8X 32 MB. tried upgrading to the latest video driver ... and it gets even worse. now it crashes the app as soon as it tries to render the Viewport3D with an ImageBrush. it ignored debug mode and just blows up and asks to send an error report to MS. if i replace the ImageBrush with a SolidColorBrush then everything works fine. the Viewport3D displays and then the DVD renders properly.
Bob Brown (of MS) also noticed that you cannot collapse WinForms hosted in Avalon. i discovered this for MediaPlayer, but it ends up being for other System.Windows.Forms controls too. posted a sample in the avalon newsgroup for others to repro. for my app i need to be able to collapse their containing Panels, but i also need to be able to overlay other Panels on top of them.