Table not selectable when using a layout in ColumnGenerator

When I create table cells with a HorizontalLayout with a ColumnGenerator, the table selection doesn’t work anymore on this cells. The mouse cursor shows the hand but the click seems not to be propagated to the table anymore.
On the cells without a Layout the selection works properly.
I’m not experienced in the GWT event propagation. So if someone could point me to where to start from or has an solution or explanation…