Bug 174701 [Viewers] ViewerRow should be reused instead of connected to the Item
Currently we create a ViewerRow ver every Item we create this can degrade performance, we should cache the row and reuse it
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/ColumnViewerEditor.java
TraverseEvent event) {
		ViewerCell cell2edit = null;
		if (event.detail == SWT.TRAVERSE_TAB_PREVIOUS) {
			event.doit = false;
			if ((event.stateMask & SWT.CTRL) == SWT.CTRL
					&& (feature & TABBING_VERTICAL) == TABBING_VERTICAL) {
				cell2edit = searchCellAboveBelow(row, viewer, columnIndex, true);
			} else if ((feature & TABBING_HORIZONTAL) == TABBING_HORIZONTAL) {
				cell2edit = searchPreviousCell(row, viewer, columnIndex,
						columnIndex);
			}
		} else if (event.detail == SWT.TRAVERSE_TAB_NEXT) {
			event.doit = false;
			if ((event.stateMask & SWT.CTRL) == SWT.CTRL
					&& (feature & TABBING_VERTICAL) == TABBING_VERTICAL) {
				cell2edit = searchCellAboveBelow(row, viewer, columnIndex,
						false);
			} else if ((feature & TABBING_HORIZONTAL) == TABBING_HORIZONTAL) {
				cell2edit = searchNextCell(row, viewer, columnIndex,
						columnIndex);
			}
		}
		if (cell2edit != null) {
			viewer.getControl().setRedraw(false);
			ColumnViewerEditorActivationEvent acEvent = new ColumnViewerEditorActivationEvent(
					cell2edit, event);
			viewer.triggerEditorActivationEvent(acEvent);
			viewer.getControl().setRedraw(true);
		}
	}