code: @Override
      public void setValueAt(Object value, int rowIndex, int columnIndex) {
          Item item = getPropertySheetElement(rowIndex);
          if (item.isProperty()) {
              if (columnIndex == VALUE_COLUMN) {
                  try {
                      item.getProperty().setValue(value);
                  } catch (Exception e) {
                      Logger.getLogger(PropertySheetTableModel.class.getName()).log(Level.SEVERE, null, e);
                  }
              }
          }
      }
docs: Sets the value at the specified row and column. This will have no effect
  unless the row is a property and the column is {@link #VALUE_COLUMN}.
  
  @param value
  @param rowIndex
  @param columnIndex
  @see javax.swing.table.TableModel#setValueAt(java.lang.Object, int, int)