In another topic the discussion was centered on the issue of editing the slideshow, something we were all hoping to be improved in newer versions. Now finally it seems that in TW 4.0 this is possible.
The online manual says: "This SlideShow is allowed to be modified by customers in which the frames could be added, deleted and the properties of the frame can also be edited."
Now, the slideshow can be edited, but no saved. When leaving the "MovieREC" window, the changes will not be saved. The most important thing from editing the slideshow is, in my case, the advantage that the scenes choosen thru thumbnails and/or any other box, will be the same edited one.