Bug 201906 [Viewers] 3.4 ColumnViewerEditor leaks ViewerCell instances.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/ColumnViewerEditor.java
rv = searchCellAboveBelow(newRow, viewer, columnIndex, above);
			}
		}
		return rv;
	}
	private boolean isCellEditable(ColumnViewer viewer, ViewerCell cell) {
		ViewerColumn column = viewer.getViewerColumn(cell.getColumnIndex());
		return column != null && column.getEditingSupport() != null
				&& column.getEditingSupport().canEdit(cell.getElement());
	}
	private ViewerCell searchPreviousCell(ViewerRow row,
			ViewerCell currentCell, ViewerCell originalCell, ColumnViewer viewer) {
		ViewerCell rv = null;
		ViewerCell previousCell;
		if (currentCell != null) {
			previousCell = currentCell.getNeighbor(ViewerCell.LEFT, true);
		} else {
			if (row.getColumnCount() != 0) {
				previousCell = row.getCell(row.getCreationIndex(row
						.getColumnCount() - 1));
			} else {
				previousCell = row.getCell(0);
			}
		}
		
		if (originalCell.equals(previousCell)) {
			return null;
		}
		if (previousCell != null) {
			if (isCellEditable(viewer, previousCell)) {