Currently of diff pages, moved paragraphs are considered a deletion and a subsequent addition. This leads to the situation that people always need to read through all moved paragraphs to make sure, that nothing has changed apart from the position. Since showing the changes comes with many technical difficulties, as a first step, the idea is to only look at moves of paragraphs, which did not change content-wise. With this implemented, users will know whether or not they need to scan the paragraph for changes, even if we can't show them yet where changes are (if they exist).
On diffs, indicate with an arrow when a paragraph has been moved and nothing else within the paragraph has changed. @Jan_Dittrich will provide a design for that.
Diff engine changes need to be implemented both for php and c++. Right now, this ticket covers both implementations. Feel free to duplicate / create sub tasks....
This is part of fulfilling wish #2 of the 2015 German-speaking community wishlist survey: T139603: Show text changes when moving text chunks (#2)