I'm not sure if this has always been in Unisphere or was added as a recent release, but I've only just discovered this feature...
The VNXe is managed by a web-based Flash application called Unisphere. This application makes use of smooth fades for menus and screen information. All very impressive, until you're on an RDP session at which point it's mildly annoying.
Fortunately there is an option to allow the fading to be turned off. To enable, go to Settings and then Preferences. Tick the box labled "Optimize for remote management access" and click "Apply Changes".
The application will now feel a lot snappier.