[Echo-list] Grid bug

[Lendvai A. <Att...@ne...>]

hi,

if you have a Grid, and add labels to a specific cell twice, then the
cell is not rendered.

grid.add(0, 0, new Label("foo"));
grid.add(0, 0, new Label("bar"));

and neither foo, nor bar will be visible, and no exception is thrown.

- 101