Grid pane lays its children outside the bounds

To reproduce:
1. Select "Check box" in the first combobox;
2. Select "Check box" in the second combobox;
3. Click "Recreate grid";
4. Cilck "Add row";
The check box will be rendered ouside the grid pane.
The same thing also happens with toggle buttons and radio buttons.
The expected behavior is like a Label performs.