Certain computer configurations seem to have a problem displaying certain Silverlight content in Mosaic Vivarium. This could include things like the file uploader and the Cage Side Assistant. A blank white area appears instead of the usual software controls.
Thanks to our friends at the FMI for finding a solution to this problem: tell IE9 to use software rendering.
Tools -> Internet Options: Advanced Tab: Tick 'Use Software Rendering instead of GPU Rendering'
Here are some related links provided by the FMI:
http://wgsnetman.blogspot.ch/2011/12/ie9-rendering-problems.html
http://forums.silverlight.net/t/248409.aspx/1
