@Override
 public void execute(final jetbrains.mps.openapi.editor.EditorContext context) {
   EditorComponent editorComponent = ((EditorComponent) context.getEditorComponent());
   SelectionManager selectionManager = editorComponent.getSelectionManager();
   Selection selection = selectionManager.getSelection();
   if (selection instanceof SingularSelection) {
     EditorCell selectedCell = ((SingularSelection) selection).getEditorCell();
     SNode selectedNode = selectedCell.getSNode();
     SNode topMostNodeInSingularContainment =
         findTopMostNodeWithSingularContainment(selectedNode);
     if (topMostNodeInSingularContainment != selectedNode) {
       EditorCell nodeCell = editorComponent.findNodeCell(topMostNodeInSingularContainment);
       if (nodeCell != null) {
         editorComponent.pushSelection(nodeCell);
         editorComponent.scrollToCell(nodeCell);
       }
     } else {
       Selection newSelection =
           selectionManager.createRangeSelection(selectedNode, selectedNode);
       if (newSelection instanceof NodeRangeSelection && selectedCell.isBigCell()) {
         newSelection = ((NodeRangeSelection) newSelection).enlargeSelection(myUp);
       }
       if (newSelection != null) {
         selectionManager.pushSelection(newSelection);
         newSelection.ensureVisible();
       }
     }
   } else if (selection instanceof NodeRangeSelection) {
     Selection newSelection = ((NodeRangeSelection) selection).enlargeSelection(myUp);
     if (newSelection != null) {
       selectionManager.pushSelection(newSelection);
       newSelection.ensureVisible();
     }
   }
 }
 private EditorCell findTarget(EditorComponent editorComponent) {
   Selection selection = editorComponent.getSelectionManager().getSelection();
   if (selection == null) {
     return null;
   }
   List<EditorCell> selectedCells = selection.getSelectedCells();
   EditorCell cell = selectedCells.get(selectedCells.size() - 1);
   return cell.getEndCell(CellConditions.SELECTABLE);
 }