Problem:

users A and B open the same empty document, and the initial document
height is the same for both views, say 100 rows;
user A goes to row 1000 and enters some text
user B is not able to scroll below row 100

Change-Id: I68efe03473c6f82d68182a951034d2e95ffa7765
Reviewed-on: https://gerrit.libreoffice.org/53996Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Marco Cecchetti <mrcekets@gmail.com>