Hi Gernot,
This is definitely not a major bug, but I just noticed it, and figure I will post it here so it is a known issue.
By no means is it a bug to lose sleep over though.
In the 9.006 IDE, you can scroll past the end of a document I think infinitely using the scroll wheel on a mouse.
Using the slide widget on the edge of the screen, it stops as it should.
Regards,
Dave