There's also a notable ideological split, a schism, in this amazing instrument combining both the aspects of a positional indicator and a navigational device in

There's also a notable ideological split, a schism, in this amazing instrument combining both the aspects of a positional indicator and a navigational device in a single widget that we call a scrollbar. Namely, it's about the question, whether the scroll thumb should be flexible in size, thus representing the size of the viewport in relation to the total dimension of the document, or not. If it is, the user can obtain information about the approximate size of the entire document nearly immediately. On the other hand, if it does not, it rather emphasizes the position of the viewport in a document and allows for more precise navigation to a certain location in the given document. Moreover, this second type of scrollbar doesn't suffer from issues with very long or very short documents. (As the second option provides a bit more usability, it was quite naturally removed in the process, we know as the history of user interfaces.)