there is no credit applet in itself in PD. What one does is use the title applet, and use the "scroll up" animation. That is what I did.
The titling app works fine for small normal titles. But in using it to make a long list of credits, I kept encountering weird bugs. For instance, the text alignment (right, left, center) kept changing, from how i set it, for particular text. Weird. I had to keep changing it back to how i wanted it.
Also, it is weird, that, unlike in word processors, when one highlights text, and changes the font, the highlighting is then gone. If one also wants to change the size of the font, one has to re-higlight. Would be simpler if that text remained highlighted, as with any other text application. Again, no major problem if it only concerns a short title. But with a long credit list, that kind of thing makes it more cumbersome. (Also, no option to underline text.)