Any time the captioning on the program is supposed to display in italic, these Zenith televisions will display the captions as black text on a yellow background rather than the normal white on black. The current FCC standards require that italicized text be shown either as true italics or as slanted text. Many captioners avoid the trademark and fraction symbols entirely just because of this problem. For more detail, see the full Line 21 character set. The words appear one at a time at the end of the line, and when a line is filled, it rolls up to make room for a new line.
Older decoders can only display roll-up captions at the bottom of the screen.
Newer ones can place captions wherever the captioner wants them. The entire caption appears, all at once, on the screen. When a pop-on caption appears, all captions previously on the screen are erased. Paint-on captions are a relatively new style. They are not used much yet, except for commercials and special effects.