b56 versus b55

Schaking and thrilling on animations and transitions , as encountered on b55, have slightly reduced but are still present.I compared playing a short slideshow, just created and using functionalities available on both the .4 version and the .5 beta version. There is no comparison,the .4 is fluid, the .5 latest version is not.
In addition on b56, when applying a border on an oval/rectangle mask, the border is no longer applied on the outside limit of the selected mask, the border can be either inside or outside the limit !!!
Under b56, as under b55, I have no problems inserting an audio file.

While I was writing the above comment, the b56 was automatically updated to the b57. By replaying a slideshow, it seems that the shaking and thrilling have been corrected, however the phenomena of the border on the masks are still there. When I created my last slideshow with b54, the problem of the border was not existing, it was perfectly matching the limit of the mask ( Incidentally when I run this slideshow with version 4.6.8, the borderline is perfectly matching the limit of the mask )!!!