Add missing wait for window shown.

Change-Id: I746a12dfa1b87a0d1393341ca3d641f73bcaee0a
Reviewed-by: Thorbjørn Lund Martsum <tmartsum@gmail.com>
Reviewed-by: Stephen Kelly <stephen.kelly@kdab.com>
When doing a PageDown or PageUp it should show the next set of cells

Before it would skip out a row depending on the size of the tableview.
Now it will show the next set of cells for the direction it is going in.

Change-Id: I02926d0b2187ffafffb63f7fff43c233b4d7d6af
Reviewed-by: Mitch Curtis <mitch.curtis@digia.com>
Reviewed-by: Stephen Kelly <stephen.kelly@kdab.com>