    @Test
    public void testGetFocusPreserveExtension() {

        ComponentGrid grid = createTestGrid();
        FocusPreserveExtension focusPreserveExtension = (FocusPreserveExtension) extractExtension(grid,
                FocusPreserveExtension.class);

        assertThat(focusPreserveExtension, is(sameInstance(grid.getFocusPreserveExtension())));
    }