GtkTreeView: Avoid interference with animation
GtkTreeView: Avoid interference with animation

The animated scrolling interferes with incremental validation.
As short-term solution, disable scrolling animation during
incremental validation. This is not a proper solution, but
it avoids broken behavior like scrollbars that are not reacting
to clicks. The problem was visible, e.g. in the list view
example in gtk3-demo.

alexlarsson/gtk,jessevdk/gtk,Lyude/gtk-,jigpu/gtk,Adamovskiy/gtk,ahodesuka/gtk,chergert/gtk,davidgumberg/gtk,jadahl/gtk,jadahl/gtk,Adamovskiy/gtk,alexlarsson/gtk,chergert/gtk,alexlarsson/gtk,jigpu/gtk,ahodesuka/gtk,ahodesuka/gtk,alexlarsson/gtk,jessevdk/gtk,grubersjoe/adwaita,chergert/gtk,jadahl/gtk,davidgumberg/gtk,alexlarsson/gtk,grubersjoe/adwaita,Lyude/gtk-,davidgumberg/gtk,jigpu/gtk,grubersjoe/adwaita,Lyude/gtk-,grubersjoe/adwaita,chergert/gtk,Lyude/gtk-,ahodesuka/gtk,Adamovskiy/gtk,jigpu/gtk,Adamovskiy/gtk,jadahl/gtk,grubersjoe/adwaita,alexlarsson/gtk,jadahl/gtk,Lyude/gtk-,jigpu/gtk,jigpu/gtk,ahodesuka/gtk,jadahl/gtk,Lyude/gtk-,Lyude/gtk-,ahodesuka/gtk,ahodesuka/gtk,jigpu/gtk,Lyude/gtk-,davidgumberg/gtk,Adamovskiy/gtk,ahodesuka/gtk,chergert/gtk,jadahl/gtk,chergert/gtk,chergert/gtk,jigpu/gtk,jessevdk/gtk,Adamovskiy/gtk,davidgumberg/gtk,alexlarsson/gtk,jadahl/gtk,chergert/gtk,grubersjoe/adwaita,jessevdk/gtk,grubersjoe/adwaita,alexlarsson/gtk,jessevdk/gtk,Adamovskiy/gtk,grubersjoe/adwaita,Adamovskiy/gtk,jessevdk/gtk,davidgumberg/gtk,davidgumberg/gtk,davidgumberg/gtk,jessevdk/gtk