fdo#65588 -  Elements Dock: Scrollbar moves into input window

This change "solves" the visual problem. But I don't think so
this is the best solution

Change-Id: I658f7a4182578e49644ae6de281f221499d61ad3
Reviewed-on: https://gerrit.libreoffice.org/6602
Reviewed-by: Marcos Souza <marcos.souza.org@gmail.com>
Tested-by: Marcos Souza <marcos.souza.org@gmail.com>