Insert a png Insert a position and zoom on you png, Insert keyframes E.g Start at 100 % zoom goes to 200% go back to 100% move it etc Now extend the length of the png Move a bit the whole in time See the effect being totally lost See also the keyframe in the effects pane being not in sync anymore with the handles on the clips timeline... btw show me unit-tests ;)
to see unit test, have a look at refactoring_timeline branch. still a lot lot to do (10 years amateur developing with no tests to recover), if you know how to write tests your help would be so much appreciated
Since then, Kdenlive evolved a lot and got much more robust on these aspects