Disable overlay scrollbar in object list
Disable overlay scrollbar in object list

Overlay scrollbars often hide some of the content (specially for
numbers, that are right-aligned).

And make the scrollbar appear only when necessary.

Fixes: https://tree.taiga.io/project/stoq/task/1582
Change-Id: I48d759c19715f4732616bcdd5495824eb3d42b54

stoq/kiwi