[Paraview] Bug: saving screenshot with screen or print palette resets background color

[Olumide]

Hi,

I'm not sure if this has been reported/logged. This bug is easy to 
reproduce. Here's how to:

1. Open a new Paraview scene, and set the background color (to white for 
example)

2. Import or create a VTK object

3. Export screenshot with the screen or print palette.

Result: the Paraview background color is reset to the default value.

- Olumide