col.setAlignment(HorizontalAlignment.LEFT);
columns.add(col);
TableColumnModel cm = new TableColumnModel(columns);
elementTable = new Table(cm);
elementTable.setSelectionMode(SelectionMode.MULTI);
elementTable.setHorizontalScroll(true);
elementTable.setDeferHeight(true);
// disable to allow CheckBox widget!
elementTable.setBulkRender(false);