SUMMARY
Feature request: the fade in/out effect should go through the beginning or end of the clip.

Currently the maximum length of the fade effect is not more than the length of the clip which you apply to. 
Sometimes it happens for example that there is a short clip at the end of the video, and I would like to apply a long fade out effect which is longer than the length of the clip.
It would be a good idea to modify the fade effect so it can be longer than the length of the clip, so for example, in the previous example the fade out effect would go through the boundaries of the clips and start to fade the video at the clip before the last clip.

workaround:
create a title clip with black background color, place on the clips which you want to apply the fade in or out effect, then use the "composite" composition to fade the clips to the black background.