This bug has been around for a while on our system, at least from 7.5.7 (recently verified still happens in 7.6.6).
To reproduce, display a Grid with more rows than fit the window size, for example 31 rows in a small window.
Scroll to the bottom row.
Change the data container size, in our case via a filter that reduces the 31 rows to 9.
The table now shows empty spaces in some areas, sometimes even full empty.
Moving the crollbar can fix part of those empty areas but not all of them.
See attached images.
I was told by support this was fixed in 7.6.5 except for Firefox browsers.
Now I just tested Firefox 47.0 and it appears the fix appliet to that as well.
I don’t think Firefox 47 fixed this.
Bug https://dev.vaadin.com/ticket/19802 is still relevant.
In your last test, was the new container size less than the number of rows that would fit without scrolling?
