[vtkusers] vtkImageViewer is displaying a black window

[Wolfram H Volpi]

When I use vtkImageViewer, it displays an all black window.
When I use vtkRenderWindowInteractor the image is displayed.
How can I get vtkImageViewer to display the image from renWin?
Below is part of the tcl code.

############ this displays an all black window
vtkWindowToImageFilter wtif
	wtif SetInput renWin

vtkImageViewer view
	view SetInput [wtif GetOutput]
	view Render

ren2 Render

############# this displays a rendered cone
vtkRenderWindowInteractor iren
    iren SetRenderWindow renWin

iren SetUserMethod {wm deiconify .vtkInteract}
iren Initialize

wm withdraw .
############

Thank you,
Wolfv