I received this from Toshibas customer support center:
" Dear Valued Customer,
Displaying any stationary images generated by a picture-in- picture
(PIP) display, Multi-Window display, computer displays, video games, stock market reports, etc., can become permanently engrained on the picture tube(s). This damage is not covered by the warranty, as it is a result of misuse. If you wish to use your TV to display stationary images, we recommend reducing the brightness and contrast levels.
Thanks,
Customer Solutions Center"